Yeah, the umpteenth of those lists, but I can relate to this one a lot (of course I would shuffle around some titles). Worth having a peek.
http://pc.ign.com/articles/101/1011624p1.html
'SPOILER':
Falcon 4.0 never played it
Diablo played it
Doom played it
Unreal Tournament never played it
Deus Ex played it
Grim Fandango played it
Fallout played it
System Shock 2 played it
Crysis played it
Starcraft played it
C&C played it
Company of Heroes never played it
The Sims played it
WoW played it briefly
Simcity never played it
Call of Duty played it
Mechwarrior 2 played it
Rome Total War played it
Sid Meier's Pirates never played it
Half-Life played it
Battlefield 1942 played it briefly
Baldur's Gate II played it
Civilization IV played it
Star Wars TIE fighter never played it
X-Com UFO Defense (Enemy Unknown) played it
Better villain, better NPC's (more interesting), overall much sleeker, better resolutions, bigger world, more side quests...but the villain takes the cake. Sarevok was cool as villains go, but Irenicus was a whole different ballgame. BG2 is to this day the single greatest fantasy epic ever made, for me. I will, however, agree with you on Civ 2 > Civ 4. 