On Youtube you can find some great amv's made by some very talented people. Many of the songs they use suit the characters to a tee. One made for Bloo uses the song "I want you to love me" and one that has alot of Frankie in it uses the song "Break my Stride". They work really well.
http://www.youtube.com/watch?v=BRrMj...elated&search=
http://www.youtube.com/watch?v=wQUHj...elated&search=
http://www.youtube.com/watch?v=JoXcL...elated&search=
http://www.youtube.com/watch?v=1Aa0KVIMsV4&NR
And finaly, this one. It's not about any particular friend in general, but I found it powerful and moving.
http://www.youtube.com/watch?v=Wi_7H...elated&search=