^yep right now quad core is the only way to go
to answer your question
for PC
Minesweeper
Warhammer
Hitman (all versions)
Warcraft (all three)
Neverwinter Nights
Poll Of Radiance:Ruins of Myth Drannor
Crysis
Call of Duty (all five)
Battlefield (1942, Vietnam and 2)
Baldur's Gate
Battle Realms
Ultimate Doom
Final Doom
Doom 2
Assassin's Creed
Heroes of might and Magic (1-5 with all expansions)
Quake-Enemy Territory
Quake 3
Worms World Party
for the Mac from like 1993 (yes I still use it every now and then)
Doom 2
Warcraft (original)
Sim City 2000
Warlords
Battle Chess
Pool of Radiance
Curse of the Azure Bonds
Secret of the Silver Blades
got a few that I have yet to play for some reason or another too
Crysis: Warhead
World In Conflict
and I am sure I am missing many others