I think Unreal and UT have some of the best weapons in an FPS. They've got a good balance, and a lot of them got away from the done-to-death handgun, shotgun, machine-gun, rocket launcher.
The weapons I most associate with Unreal are:
ASMD
Flak Canon
GESBioRifle
Razorjack
The secondary and combo fire modes were a welcome change in Unreal, and the trend should continue to all weapons designed for Unreal 2.
The other games that had some inventive weapons, IMO, were Half-Life and Opposing Force. The bio-weapons were just so funny, while being really useful. I mean, who can forget the Barnacle Gun or those little critters that scamper off to attack your enemies (or you, if you're not careful).
I want to see some really inventive stuff in Unreal 2. Including some more traiditonal weapons is a necessity, I guess, but I don't want to have to rely on them to get me through the game.
Check out the thread I started on the Unreal II forum, about Your Weapon Ideas. There are some really cool ideas in that thread, too. You can find it here...
http://ina-community.com/forums/showthread.php?threadid=94694