I secretly desire your console!

First of all, if you get a PS2 try to get the newer slim version. Not only does it play burned DVD movies, not only does it come with network adaptor built in, but it's also alot smaller and way more stylish. Plus it's newer so there's less chance that it'll break.

Ace Combat series: Start with 04 (you can find it for like $10 now, deal of a lifetime) and then get 5 and Zero if you like the series. The best jet fighter games ever made bar none. Period. Tons of unlockable planes and huge mission variety keep the action fresh and frantic the whole series. Plus it has some the the best music in gaming.

God of War: I second the recommendation of this game. I just beat it last week, and WOW! What a game! Great action and platforming, great level design, and an enjoyable story about Kratos' quest to kill Ares, God of War. This game is epic. This was many a magazine's game of the year. And it just went on Greatest Hits, so you can find it for a mere $20. Mortal!

Metal Gear Solid 3: Subsistence: I also second this one. For a mere $30 you get one of the best PS2 games ever, plus tons of features that the original MGS3 didn't have, such as the absolutely amazing online mode, rotatable 3D camera, and the original 2 Metal Gear games from the MSX (with English translation). If you play just one online game for PS2, make it this one!

Splinter Cell: Chaos Theory: Even though it's also on Xbox, Chaos Theory is a great game on PS2. Great graphics and gameplay. Stay away from the online mode though, it's crap compared to the PC and Xbox versions plus you'll likely get totally owned. Stick with Subsistence if you want an online PS2 game. I would also recommend Pandora Tomorrow if you like the series, I like it just as much as Chaos Theory. Unless you really like the series, the first SC game feels a bit dated compared to Chaos Theory and might not be worth it (but it can be found for about $10, which is a plus).

Zone of the Enders: The fastest and furious-est action game on PS2. Though both ZOE games were a bit short, they are totally worth it (especially since they're both really cheap now). Intense fast paced flying mech action produced by Hideo Kojima (of Metal Gear fame).

Resident Evil 4: Though it came to Gamecube first, the PS2 version is every bit as enjoyable, even if you've never played a RE game before. The situations in the game are amazing and freaky intense. Great bosses too. Plus the chainsaw-wielding maniac is like the scarriest thing in a game ever. The PS2 version also has a bunch of extras that the 'Cube version didn't have. A very fun game. And it won Spike TV's VGA game of the year if I remember correctly.

Gran Turismo 4: Make no mistake, this is THE driving simulator. If you don't like racing games then stay away, but this franchise got me into racing games in the first place. Great graphics, awesome car handling physics, detailed car upgrade system, and hundreds of unlockable cars. GT3 might be more worth your money if you're new to Gran Turismo as it's a little easier for beginners to get into and you can find it for cheaper.

Jam it back in, in the dark.