My question is why a game as graphicaly cutting edge as Assassins
Creed, the first game to support DX10.1, does not even include AA for
higher resolutions (such as 1920x1200).
I've played lots of other games that have AA in them at this
resolution, WTF IS THE PROBLEM??

HOW DO I MAKE AA WORK AT 1920x1200 ON THE STEAM VERSION, DAMMIT?!

There is *NO* Assassin.ini file to modify in the steam version. No .ini file to modify at all really.

Forcing it through Nvidia software OR NHancer does *NOT* work either.

PLEASE HELP!

no nvidia card has pixel shader 4.1 so you cant get DX10.1 on your card.

I know that dammit. This isn't about DX10.1. I was just pointing out the *EPIC* failure on Ubisofts part to enable something as basic as AA.

Actually, there is an INI file that you can play with.

Windows XP method 1:
Go to %appdata%\Ubisoft\Assassin's Creed. Find ASSASSIN.INI . Modify as you wish.

Windows XP method 2:
Go to Application Data\Ubisoft\Assassin's Creed. Find ASSASSIN.INI . Modify as you wish.

Other notes:
TweakGuides.com has a modification guide for Assassin's Creed. I'm actually a little surprised that you didn't take a look there first, that's where most gamers go first to figure out what they can do to tweak a game on a far advanced level than what a game provides stock-wise.

Granted, Assassin's Creed is a console port and therefore has limited modification parameters. I've never had to run a game at your intended resolution (1920x1200), so I place NO guarantees on success rate of forcing anti-aliasing through the INI file.

^^ He installed the Steam version. They have no Ubisoft folder in their appdata/Application Data...

@Ashertab: try in your Steam > SteamApps > *your account* > "AssassinsCreed" (or whatever the game's folder is named)? Also checked for .cfg file?
Go to registry (regedit),
Navigate to the key
[HKEY_CURRENT_USER\Software\Valve\Source] see if you find AC, maybe in the subkey you find settings?

Thanx guys. found it.

Lord knows Ubisoft would've never got back to me

Ubisoft probably relies on its users for technical support. At least that's what I see; when users try to get help from the "official Ubisoft tech support" tickets via the appropriate page, the users get very generic answers ("try checking for spyware!") ... Um. No. That's not REAL technical support, I could get someone in middle school to work at Ubi-tech support then.