(Not strictly based upon just this years games but I felt like doing it)
Best Firstperson shooter: Halo 2
No surprise here, absolutely sublime with plenty of modes to keep you coming back, more of the same but if it's the best then it doesn't need fixing.
Worthy mentions: Riddick:EFBB, Ghost Recon 2, Rainbow Six: Black Arrow
Best strategic game: Splinter Cell: Pandora Tomorrow
Nothing comes close to the sheer enjoyment that can be gained from a well played well executed bit of onlone co-op on SC:PT
Worthy mentions: Halo 2, Ghost Recon 2, Gladius, Wrath Unleashed,
Best realtime strategy game: Goblin Commander
Hmmmm slim pickings here really, the title may very well belong to Kingdom Under Fire which I have yet to play.
Best turnbased strategy game: Gladius
Having finished it originally on normal in just under 80 hours completing every battle I could I then came back 6 months later to finsh it off on the harder difficulty in under 40 hours. Interesting combat, plenty of bits and pieces to play with and customise, varied battles and characters.
Worthy mentions: Robin Hood: Defender of the Crown
Best Beat 'em up: Wrath Unleashed
The pick up and play factor is unmatched and the perfect balance of strategy and simple gameplay makes this one of the best hybrids ever made. Lucas Arts have some balls after all.
Worthy mentions: Buffy: Chaos Bleeds, Gladiator: Sword of Vengence
Most underrated game of the year: Thief 3/Deus Ex 2
Hmmmm tough one. It's a tie between Thief 3 and Deus Ex 2. Thankfully both games are expected to receive more outings in the future.
Worthy mentions: Sudeki, Gladiator: Sword of Vengence, Wrath Unleashed, Phantom Crash
Hardcore game of the year: Metal Dungeon
Has to be. Pretty much the only game on xbox requiring 'power levelling' a strange approach and and odd combat system. The visuals aren't up to much but the strange attrition gameplay and exploration make for a strangely addictive title. In some ways the combat system is similar to KOTOR except you have a much higher chance of losing your entire party and you can only save when you exit the dungeon meaning an hours worth of play can dissappear because of one too many risked encounters.
Worthy mentions: Phantom Crash, Gladius, Morrowind:GOTY
Most innovative game of the year: Splinter Cell: Pandora Tomorrow
Like it, loathe it: the simple fact is it deserves recognition.
Worthy mentions: Halo 2, Thief 3, The Thing, Psi Ops:TMC, Second Sight, Breakdown(?)
Biggest dissapointment of the year: Finding out a decent MMPORPG wasn't coming to the xbox any time soon.
Worthy mentions: Judge Dredd, Max Payne 2, Tenchu
Best Adventure: Deus Ex 2
Worthy mentions: Riddick:EFBB, Thief 3
Best realtime RPG: Morrowind
Worthy mentions: KOTOR, Fable, Sudeki
Best turn based RPG: Gladius
Worthy mentions: KOTOR(ish), LOTR:TTA
Best Movie-tie in: Riddick: Escape from Butcher Bay
A quality title from start to finish, a little on the short side but replay value is assured as various parts have multiple routes and there are different approaches to take. Playing the character of Riddick is great fun.
Worthy mentions: LOTR:TTA, The Thing
Best Hack 'n Slash: Fable
Definately snatched the title away from anything that could be considered a rival as a hack 'n slash game.
Worthy mentions: BG:DA2, D&D Heroes, Blood Rayne, Buffy: Chaos Bleeds
Most immersive game of the year: Morrowind
Too many late nights and early mornings of this year have I spent exploring the world of Morrowind.
Best Mech game: Phantom Crash
Without a doubt of best approach to Mech gaming on the xbox.
Worthy mentions: The one that costs 120 quid that I've forgotten and so have you. :P
Best Stealth game: Tied. Offline: Thief 3. Online: SC:PT
Best Racer: Burnout 3
It might've only lasted a glorious 2 weeks but it's still the most fun I've had on an xbox racer.
Shortest lifespan: Star Wars: Battlegrounds
Within 12 hours of owning it I was putting it up for sale. Stats would have saved it.
Best use of custom soundtracks: Burnout 3
If it didn't have the option I think a fair few copies might've found themselves quickly returned.
Best sports title: Death Row
Everything else would become awful after a half hour of play.
Most 'dumbed down' title of the year: Fable
Most of the extra additions lacked enough depth to really make them worth bothering with, why bother owning a house, getting a wife and trading bits of wood? Pointless options without the inclusion of any real incentive to use them.
Best story: Thief 3
Without giving anything away: this has it all.
Worthy mentions: KOTOR
Best music: Halo 2
Incubus and Hoobastank etc.
Most infuriating game: Wrath Unleashed
ARGH! Crazy evil AI from hell on the higher settings!!
Most 'old school': Robin Hood: Defender of the Crown
Plays like a CDi game, good oldschool gameplay and worth a look if you're after some cheap old style gaming.
Weirdest purchase of the year: New Legends
Bit too shallow in combat options, strange story that isn't explained very well and you can basically run through the levels rather than fight through them. Very odd but fun to play about with.
-AI that reacts satisfyingly different each time you replay a section and face them in a massive battle in a massive area
Although I preferred the atmosphere of Riddick, it's more of a corridor shooter and it's got nothing on Halo in multiplayer (because it has none and they've admitted they couldn't equal the standards of Halo in multiplayer which is why they didn't include any).
Although Halo 2 really is a very poor FPS, in single player at least. And not having Live, Riddick is my favourite Xbox FPS this year.