I dislike this maturity argument. Gameplay is key in a game for me, which is partly why the argument annoys. I don't play games for stories for the main part, although I can appreciate what they can add when done to a standard I approve of, which is quite rare, tbh. To use an oft-cited example of what a mature game is, let's take GTA. The game isn't good to me because of its violence or story as both don't concern me, but the freedom offered within the game. If the lead character was Mario, the prostitutes were Princess Peach clones that you played Rock, Paper, Scissors with to gain health and/or coins (as opposed to taking to another location and having sex with, which was amusing the first time), you shot water guns and it was set in The Mushroom kingdom, it wouldn't bother me as long as the freedom to play was still there. Naturally, I could compare the rest, but I'm sure you get the picture. Or at least I hope.
This is one part of why the "Mature" argument bores. The other is that when I go to website or forum with people there with way more knowledge than me (and most likely everyone posting here) about games (people that teach game design, make games, give lectures on the topic, etc.) the topic of "mature" Vs. "Childish" games never appears. I wonder why that is? Is it that they can see past the 'clothing' the game is wrapped in? Is it that they are secure with their own masculinity/femininity and maturity that they need not play games to make themselves feel mature or to prove their masculinity/femininity? I'll leave you guys to work out that for yourselves.
Back to the topic of my top 10 for GC. In no order, here goes:
F-Zero GX
Super Monkey Ball
Pikmin
Viewtiful Joe
The Legend of Zelda: The Wind Waker
Metal Gear Solid: The Twin Snakes
Metroid Prime
Eternal Darkness: Sanity's Requiem
Super Mario Sunshine
Ikaruga
Please note: I haven't played ToS, Baten Kaitos, Paper Mario 2, Resident Evil 4 and Wario Ware Inc yet. So they could easily work their way in by the time I have.