So, because I evidently have too much free time on my hands, I decided to trace the lineage of Prince George of Cambridge.
https://www.dropbox.com/s/xdcgv4oxf91vsyf/Royal Ancestors.xlsx
In order to open the Excel spreadsheet you need Microsoft 2007 or newer. It will want you to download it (there are no viruses attached), and it's a large file so it can be a bit slow to open. Because of the size I'm not able to upload it to Google Docs or Skydrive in a way that will enable you to open it without downloading it, but I might to a condensed version of the tree later on that is more Internet friendly.
A good part of the reasoning behind my decision to do this tree was the argument that Diana and the Spencer family is in some way more "royal" or more "British" than Charles and his family. I wanted to come to some kind of conclusion as to whether or not this is really true.
In collecting this information I used Wikipedia and The Peerage thoroughly, but no additional sources. The way I went through this was to click through all of George's ancestors on Wikipedia, adding each one until I hit a dead end, then repeating the procress on the Peerage. I know that there are people missing, but I think I got most of George's ancestors (and to go through it all again to find any missing people could literally end up being months of extra work which I'm not interested in doing at this time). For the most part, I accepted the lineage as presented by Wikipedia when there were conflicts, unless either the Peerage one made more sense or lead down a more interesting path.
For the most part, I tried to present places in English, although I wasn't always successful, and I varied in my use of name spellings (I prefered the English ones for more recent people, but not always for older people). The only titles that I included were British ones, the rest are rendered simply as "of". That said, a number of individuals (primarily monarchs, but also nobles and other people who are of note in my opinion) have been highlighted, and the additional tabs note who these people are, how many children they each had, and how many of their children George descends from, as well as which way he descends from them in - be it through his paternal great-grandparents or his maternal grandparents, of which each has a colour-coded line.
I chose to highlight the monarchs who are the most recent royal ancestors of George - namely the British, Danish, and Russian monarchs. In the case of the British and Russian monarchs, I also highlighted the realms that immediately precededed them - in the case of the British, I went further by also highlighting the additional houses that came into play in English and Scottish history (the exception being the Hanovers and Saxe-Coburg and Gothas, as those titles changed too frequently before merging with the British crown for me to keep track of). I chose not to add a specific highlight to the Greek monarchs, as George is only descended from one of them, although I did count George I of Greece in the overall monarch count. Similarly, I also highlighted the two Earldoms from which George most recently descends - Strathmore and Kinghorne and Spencer - as well as their various predecessors.
The others that I highlighted include the children of Edward III and John of Gaunt who survived to adulthood, the various claimants to the Scottish throne during the Wars of the Scottish Independence, the people who bridged the gaps between British monarchs, nobles and royals who are now known most for having had a large number of children, two English consorts of extra significance in my opinion (and who had multiple husbands), and other people of historic significance. I also flagged Mary Boleyn. I chose to assume that her husband was the father of both of her children, and not Henry VIII, but I wanted to highlight her just in case Henry was in fact the father. If he fathered either of her children, then George is a descendant of Henry through his paternal grandmother, and if Henry fathered specifically Mary's daughter then George is also descended from him through his paternal grandfather.
In drawing up my conclusions I looked at the monarchs of 25 different realms (for a total of 945 monarchs), who were kings or emperors. I tried to look specifically at realms that appeared frequently in any of the Mountbatten, Windsor, and Spencer lines. With the exception of the Russians and Greeks, I didn't count any realms where only a few monarchs appear in the tree, but not many. The reason why I chose to include the Greek and Russian monarchs is because of their recent relationship to Prince Philip. As such, this does give a bit of extra weight to the Mountbatten line - this inclusion gives him 10 extra monarchs.
With this in mind, of the 945 total monarchs possible, Prince Philip descends from 394 of them (384 without the extra 10), HM from 387, Earl Spencer from 372, Frances Roche from 253, Michael Middleton from 174, and Carole Goldsmith from 191. As such, I would conclude that Diana's father was from an ancestry that was about as royal as either of Charles' parents, although not as recent and not from as senior of a line. I would not conclude that Diana herself was as royal in ancestry as Charles, though, as her mother's line is considerably less royal in origin.
Narrowing that, I looked specifically at the monarchs from Great Britain - the British, English, Scottish, Welsh, and Wessex monarchs. There, out of 156 possible monarchs, the Mountbatten line descends from 64, the Windsors 70 (including HM), the Spencers 65, the Roches 56, the Middletons 45, and the Goldsmiths 46. In this, Earl Spencer narrowly beats out Prince Philip - the Earl was descended from 1 more English and 1 more Scottish monarchs than the Prince, while the Prince is descended from 1 more British monarch than the Earl. Of the 12 British monarchs that George descends from, 8 of them are through his paternal grandfather, 3 through his paternal grandmother, and 1 (James I) through both.
Interestingly, though, while the Queen may be descended from more British monarchs, Earl Spencer is descended from more of the children of these monarchs. Out of a possible 603 (acknowledged/recorded) children, George descends from 158 of them; 111 through the Mountbatten line, 139 through the Windsors, 142 the Spencers, 96 the Roches, 62 the Middletons, and 67 the Goldsmiths. This does not necessarily mean that Earl Spencer had more lines of descent from British monarchs than the Queen, just that he descended from more individual children than the Queen. The difference appears in how many grandchildren, great-grandchildren, etc, each would descend from. A quick example of this would be that George descends from Christian IX of Denmark through two different children - George I of Greece and Alexandra of Denmark. As Christian IX is a descendant of George II of Great Britain, this gives George of Cambridge two lines of descent to George II, through 1 child.
I'm not sure if I agree with the statement that Diana was more British in ancestry than Charles. Both have a lot of ancestors who were lived in Britain, both have a lot of ancestors who didn't. Both also have a lot of ancestors who weren't born in Britain but later immigrated there and died there. Is someone like Queen Victoria, who had many close ancestors from Germany but herself was born in, raised in, and died in England, to be considered German or English? How about Mary of Teck, who like her grandmother-in-law was born in and would die in Britain, but was "of" a Germanic state and had German ancestors (as well as a fair share of British ones)? I think there's a lot more that is British about the House of Windsor than (some) people like to admit, and the whole idea that they are some how not British but German is really just xenophobia and Germanophobia.
An interesting thing that I noticed in this project was that the Queen is descended from 2 pre-Hanoverian monarchs that her father weren't descended from from, Henry IV of England and Alexander II of Scotland. In turn, William is descended from 3 pre-Hanoverian monarchs that his paternal family aren't descended from, Charles I, Charles II, and James II. This means that the only English or British monarch who has confirmed descendants alive today that William and George aren't descended from would be William IV. There are a few Welsh monarchs who do not appear in this as ancestors of George, had children, and may have known living descendants today, including Rhodri ab Owain Gwynedd who does have living descendants. There are 4 Scottish monarchs who do not appear as ancestors of George, had children, and may have known living descendants today.