EidoMwashi

There's so much good stuff to choose from! This's gotta be one of my favourites though:

This is quite possibly the best thing on the internet.

I'd recommend the Medievil games, not sure how well they've aged but I remember loving them at the time. Also Bust-A-Groove's a pretty awesome game to play on multiplayer if you're in the mood for a quirky rhythm/fighting hybrid. You can't go wrong with Metal Gear Solid 1 with the VR Mission pack either.

Windwaker mostly, along with various other gamecube games because it's the only console I have at university. Also because Windwaker's just generally awesome.

Single player all the way. Multiplayer's fun for a distraction but I've always struggled to get really invested into it, except for maybe Street Fighter 4 and Mario Kart.

@killerfridge: I second this. Way of the Samurai 2 just seemed more open and the story was just generally more compelling. Although Way of the Samurai 3 was still pretty fun and worth playing, gotta love being able to draw your sword at any time.