I'll only list consoles I've had a lot of experience with (so even though I owned an NES, GBC, and a PS1, I'll ignore them).
N64 - 9.5 - Some of the greatest games of all time (including THE greatest game of all time, the Ocarina of Time), but they were few and far between.
PS2 - 10 - Much like the N64, it had some of the greatest games of all time, but plenty more on top of that!
GC - 8 - I bought a GC pretty late in it's life (when it hit $99), but it kept me quite content between SMS, SSBM, LoZ: tWW, and other games. It had some awesome games, but it didn't compare to its awesome predecessor, the N64.
Wii - 9 - The premise is awesome, but the controls haven't been utilized quite as well as I'd hoped (yet). The awesomeness of TP, SMG, SSBB, and MKWii still warrant a 9, however. And then there's the Virtual Console. :D
PS3 - 8.5 - Games like Uncharted have been excellent, but overall the software library is somewhat lacking (particularly for someone who cares little for GTA). However, Blu-ray has been awesome, and the ps3 in general is a beast of a machine. This in combination with what games it does have warrants the system an 8.5, but with MGS4 hitting in two days and in-game XMB just a week later, it should be a 9 very soon.
DS - 9 - This is my most recent purchase. I'm currently addicted to Pokemon Diamond, and I still have Phantom Hourglass, Prof. Layton, and others waiting in the wings!
PC - 9.5 - What can I say, it's the PC. This would be a 10 if I hadn't run into so much trouble after upgrading (if you want to call it upgrading) to Vista.
