My guess is that TPQ decided to change the top friends list to bands that 1) she likes and/or 2)Billy likes, and 3)bands that are 'in' that cite some vague inspiration by SP.
You will notice that SP relevant bands like Garbage, Fountains of Wayne, Mike Garson, David Bowie, Ivy, and Kill Hannah are absent. Really I think at least some of these bands/artists should be on their list.
And if they are going to not put SP fan pages up on their top friends list, they should at least do us the courtesy of putting up the SP Fans of the World (run by an Australian fan) up on the top friends list. After all, the guy created it for the intent of acting as gateway for all the SP regional pages, including ones that TPQ has not had the chance to add to the SP fan page myspace directory.
And to perfectly honest, most people don't even pay attention to that list, or know it exists. I came to this conclusion after seeing people start up pages for cities or countries that already had 'official' SP fan pages. Not to mention when they had that SP myspace FAQ, where it explained why people couldn't add songs, there was still several people a day asking why they couldn't add the songs on SP's profile to their pages.