I'm not entirely certain why I like so much the song "Cry Me A River" by Justin Timberlake, which, um I really like, which, what, 2004?

For 2005, though, I thoroughly recommend Dean Gray's remix of "American Idiot" by Green Day, which you can easilly find by way of bittorrent or newsgroups, but so is also the best thing to happen to mash-ups maybe, ever, but certainly in a long time, otherwise.