C64 is not a console..... but anyway.
It would have to be the Dreamcast, it is still an amazing little machine. Small, well designed one of the better graphically of the time. Force feedback, little micro games in the memory cards... nice little touches everywhere.
I still have a mint Dreamcast boxed with all the gear, keyboard, mouse, light guns (shame they dont work on Plasma/LCD screens) modem...
I even have a custom case which I'll prolly never install... there's a HDD hack for them and if you're lucky you can pickup a NIC for it.
Top that off with a VGA adapter it's fantastic.
Xbox, this is great too, mod it stick a larger drive in it and it becomes a multimedia center plus mame box :-) (Or Amiga emulator... lol)
Classic consoles would have to be the master system, have found memories playing my girlfriends at the time... I even purchased it off her... still have it and it still works.