It all comes down to preference. I personally do not care for handhelds at all, so i'd say get the 360.
They are two totally different gaming systems, but I'd go with the 360. I'd only choose the PSP, if I traveled a lot, and that would still be a tough choice. Halo 3 is the only reason that 360 is/will be better then any current/near future console out there.
if you got the cash get both...but a console is always gonna rape a handehld...no matter how awful the 60 is it will always beat the psp by far. oh and if u get the 60...only get PZD - Perfect Dark Zero and CoD2 -Call of Duty 2. if u get the psp....only get DvD's and Ridge Racer....and preorder FF7 for this spring and preorder Bboy ....a breakdancing game.