Zeiss Planar 80mm on my Hassy. Classic, classic look.
30mm f1.4 Sigma on my 20D/550D - as much as it has it's limitations, I have been extremely happy with the results from this guy.
Rokkor 50mm f1.4 on my Minolta for 35mm.
I don't really use zooms, but if I did, a 17-50mm would be all I'd go for.