Splinter Cell's always had a legit soundtrack, I think. Courtesy of Amon Tobin, some guy I've never heard of.
TF2 unrelated, EvilDeadalus just used Splinter Cell music for the video. It's actually 4 songs melded into one suite in this, but I can't find just a single track version anywhere. It changes as you play the level depending on whether you're undetected, being searched for, running away, or fighting dudes. Nifty!
I actually did know before this thread that Akira Yamaoka composes Silent Hill's music, which has always been awesome.
The Dark Hospital's theme in the first game is probably my favorite, but I couldn't find it. Of course, it's also dynamic like Battery and rises to crescendos when you go into a particularly shitty part of the hospital, so I probably wouldn't be able to get a good version anyway.
And Koh Itani's stuff in Shadow of the Colossus.
AND AND AND everything ever in a Metroid game. But mostly this!
No idea who composed it.