well the current Xbox is only a 32-bit machine....
in the PC world the pentium and athlons are 32-bit... but focused on other things rather than 3D world rendering.... the new Athlon 64, and 64FX are 32/64 bit hybrids.... capable of running 32 bit code and less (8, 16 and 32 bit code) and the 64-bit processor only capable of 64-bit processing....
atari 2600 - 2bit
atari 5200 - 4bit
NES - 8bit
SNES - 16bit
Turbo Graphix 16 - 8bit
Jaguar - dual 32bit
N64 - dual 64bit
Playstation - 32bit
Saturn - 32bit
Dreamcast - 128bit
xbox - dual 32bit (semi sychronous 32bit processor)
ps2 - advertised as a 128... but is more or less a mish mash of processors on the same die
ps3 - same as above... a massive mish mash of processors... plus the fact that networked computing may be involed makes things even harder to predict the power...
xbox 360 - if all is correct looks to be a 3x dual core power PC processor each would be 64-bit
please feel free to correct any of this... I'm doing this from memory and didn't take the time to check my answers.
and to clarify the bit idea... it's nice.. but I would be reluctant to call a Cray based on pentium processors a 32bit machine... seeing that the last one that I was listed as being built had 1024 pentiums in it.... that's a far cry from the considering your PC as a comparable machine...
PS3 Slim 320GB
PS2 v11 exploit w/300GB Maxtor
PS2 v10 exploit w/80GB Samsung - Network Games
PS2 v10 exploit w/60GB Samsung - Network Games
PSP 1001 3.52M33 w/10GB total storage
NDS DSReal 4GB