The last Perfect Dark was pure mince, but an upgrade of the N64 version would be most welcome. That and Goldeneye.
I also can't recommend Jetpac enough - free for a trial on Xbox Live, but worth buying because of the cheap price and the fact you can play an updated HD version, or a complete port of the original ZX version, complete with colour clash.
Shadow Complex is also awesome, but like the nearest equivalent - Gunstar Heroes - far too short.
the finest console ever made, were it not for the unforgivable reliability issues
I now view the inevitable 360 replacement as a minor nuisance compared to the PS3 going tits-up and taking all your HD data with it.
The main issue I've had with the 360 is the controller designed for lizard-people from Venus rather than human being-sized hands. If it was better-designed, I'd play the 360 far more often, but the layout is counter-intuitive unless your first console experience was the Xbox controller, ironically making the biggest design failure of the PS3 its biggest asset for me - the controller is identical to the last few iterations and still heavily derivative of earlier consoles like the Mega Drive and Snes, while the 360's feels like a chunkier Dreamcast pad (an impression not helped by the colour scheme), which I also really hated.
A nerdy complaint, I know, and hardly a deal-breaker, but it does bug me now and again.