Torchlight

Attention Diablo II fans:

Stop what you're doing and download the free demo of Torchlight.

It's pretty much a complete Diablo clone, made by some of the same people. That might sound a little lame, but it's the best way to relive the awesome experience of those games without giving yourself amnesia. Sure, you could wait for Diablo III, but who knows what its release date will be or even what kind of PC you might need to run it?

Like the original Diablo, Torchlight takes place in a single town with one massive dungeon. There's different character classes, hordes of monsters to fight, a ton of loot to collect and equip, and even an animal sidekick who fights by your side sells your crap for you so you don't have to leave the dungeon all the time.

The single dungeon has a number of completely different looking areas and the floors are all randomized. The graphics are simple but attractive and the game will run on almost any system, even a netbook.

Once you finish the main dungeon, you can work on one with infinite levels or retire and leave your next character an heirloom.  

I recommend getting the demo or full game over Steam, but there are a number of options. The demo lets you play a few floors and reach character level 7 or so. If you upgrade, you can keep on going from where you left off.

There's no multiplayer yet, but a fan mod might enable that later.

I still have a ways to go before I'm finished, but I'm amazed at how the time flies when I'm playing this.

Here's some screens from the official site: