M4A1 rifles are seen in the hands of Bill's assassins during the wedding massacre.
Custom EMF Hartford 'Pinkerton' (Bird's Head Grip)
Bill's (David Carradine) handgun of choice is a nickel plated EMF Hartford 'Pinkerton' chambered in .45 Long Colt and with a bird's head grip attached. Bill seems to carry it with him into the sequel as well, this time sporting some type of custom muzzle brake.
O-Ren Ishii (Lucy Liu) is seen using an H&K PSG-1 sniper rifle to assassinate a man during the anime segment.
Norinco Type 54
During the anime segment, Matsumoto's guards are seen armed with some variants of the Tokarev TT-33 pistol, probably the Norinco Type 54, given the Asian setting, but it's impossible to tell for certain. The slides only lock back half way when empty.
Desert Eagle
O-Ren and a bad guy are seen using .50 AE Desert Eagle pistols during the anime segment. O-Ren uses one to great effect to kill to thugs, blasting off body parts with each shot.
Beretta 92FS
In the anime segment, Pretty Riki uses it to ignite liquor bottles in O-Ren's house.