I started typing out a big spoiler tagged post of various Blizzard track's but it go to about 30 videos and the post preview was basically lagging like crazy at that point.
So I'm just going to pick one track per game back to the Diablo I (which will still be around 30 odd tracks, but y'know) (EDIT: I lied, and went right back to Blackthorne) and try and avoid the more grandoise/bombastic epics that Blizzard are known for to give a more diverse sample.
The end result of scouring back through nearly 30 years of Blizzard games is that I could easily sit there and listen to their soundtracks all day as much as SQEX ones. Heck, pretty much any single WoW expansion soundtrack is hours of listening pleasure on its own.