In terms of an available library of potential games it can play... the PSP-go would have to be mine, got 1 tucked in behind my TV packed full of emulated goodness from all generations, having 1 tiny black bundle of joy filled with GB/GBC/megadrive/snes/psone/GBA/CPS1+2/Mame and of course the psp library itself just can't be knocked when hooked up with a ps3 controller.
As an actual unmodified system going on just its own series of games I'd be so torn between the X360 and GC that I'd never happily sit on one side or the other, both have given so much between Smash/Mario Sunshine/Pikmin/MGS twin snakes/RE4/REmake/RE0/Metroid Prime but then you got Halo/Gears/Forza/GTA3->5/Guitar hero 2->6/Portal1+2 on the x360 really just a Sophies choice between those 2.
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