There's too many to count. I admit to being a sap and feeling all emotional when I hear Suketi De Na, the end title theme music for Final Fantasy X [I got sucked in bad by that sombre ending...
If we're talking purely end theme music the Metal Gear Solid series always had good end music. I'm a particular fan of Metal Gear Solid 1's end theme. Very Celtic-sounding.
That link is to a video which plays the song [though not footage from the game.]
If you are into game music though, go to http://www.ocremix.org
It's an interesting site I came about a few years ago whose sole purpose is to remix game music and make it sound better/different etc. There's some interesting tracks there ranging from the usual Chrono Trigger/Final Fantasy compositions, to Super Mario Bros and even the occasional obscure track. Usually it's from games ranging from the early days to kind of the mid-nineties but they used to have some really good tracks from Silent hill which would have been great backing tracks for a Halloween themed party.