I didn't want to derail Xtremegamer's thread but I'm interested in your opinions, as collectors, on which games define the Xbox for you. These aren't necessarily collectible in the sense of rarity or cost, but more because of the subjective value we assign to them. For example, Blinx is neither rare nor pricey, but in my opinion it contributed in defining the Xbox by being its (failed) attempt at a Sonic/Mario type mascot. Basically, what games would you have to have in your collection in order to create a snapshot of what, in your mind, the Xbox was?
Sorry if this thread is redundant. There are currently two dealing with rarity, but I'm not interested in collectibility in the marketplace sense so much as in the personal sense.
For starters, I would include:
Oddworld: Munch's Oddysee
Oddworld: Stranger's Wrath
For being great games as well as the swansong of a great series
Psychonauts
For being the best version of one of the generation's great cult classics
Blinx 1 & 2
Brute Force
Azurik
Voodoo Vince
For better of for worse, these games are definitive Xbox failures - not necessarily due to quality.
Halo 1 & 2
No need to explain
Grabbed by the Ghoulies
Conker's Bad Fur Day
The Rare acquisition is one of the big Xbox stories
Panzer Dragoon Orta
Gunvalkyrie
Otogi 1 & 2
For being exclusive and unique in design or art direction
Buffy: The Vampire Slayer
Chronicales of Riddick
licenses with a cult followings, and good games
Star Wars KOTOR 1 & 2
Jade Empire
Sudeki
Morrowind
Fable
The best of the exclusive Xbox rpgs
Ninja Gaiden
Dead or Alive
Dead or Alive Xtreme Volleyball
Soul Calibur 2
Shenmue 2
Phantom Dust
Crimson Skies
Splinter Cell
Mechassault 1 & 2
I could go on, but I'd like to see what others would add.