I'll nominate Galaga then, since Space Invaders gets the same rating. Also, Counter-Strike; it's a wonder that that classic hasn't been up yet.
Space Invaders: 8.2/10
The Oregon Trail: 9.7/10. Favorite edutainment game of all time, and I had a lot of fun playing it. I still do. I still remember that epitaph I wrote the one time I died (very recently), and the trails I discovered as a kid. Awesome.
Super Mario Bros: Haven't played it.
loljk; 8.2/10 for Super Mario Bros. Good stuff by Nintendo, if not difficult and often confusing.
Okami: 8/10. Meh...Okami is a very beautiful game, but its controls can be annoyingly unrecognizable, it's very long while being repetitive, and the story has a bizzare focus that makes it hard to get a steady grip of the plot. Combat is decent, if not easy and, well, repetitive.
I'm going to play through Okami one day and see what I think of it after the end. Never actually finished Okami, but I can try getting through the entire game.
No More Heroes: 6.9/10. Fun boss battles marred by that goddamn cash-for-battles system where you grind through the poor minigames. Repetitive sound at times, too. But, hey, it's memorable enough in a sea of Wii games often far worse than it is.
Portal: 9.8/10. Valve did an awesome job with its portal physics, in creating one of my favorite current PC games of all time. GLaDOS was weaker here, granted, but so much better in the sequel that that complaint only made you wonder more. I also loved the style of puzzles given; a controlled environment where you're given a few tools (with logic) to power your way out? Sounds fantastic, and it works that way.