As far as traditional controllers go, my favorite is the 360's. That was actually the deciding factor when I was choosing between a new Slim or Elite, that and 360 at least is backwards compatible with xbox. IMO the PS3 controller and 360 controller each have their own faults though. Personally I do no like the analog sticks on the PS3. Theres just something about them...too loose or too much movement...something. On the 360, obviously the D-pad is not great. Also, love the triggers on the 360 compared to LR2 on PS3. So...perfect controller for me: 
I would be fine with the original xbox button and ABXY. too bad i dont have like $1k to give to ben for a couple of these.
I've thought of how amazing the N64 and GCN would have been if it had the new Classic Controller Pro back in the day...it would have reigned.