The best ARPG to keep you busy until Diablo III, and at $20.00 it's a deal that can't be beat!
This may be Runic Game's 1st Title, but they had lots of practice to get the formula right the staff includes former Diablo developers as well as Travis Baldree who created Fate, with Mythos as basically a dry run.
The formula is fairly simply Collect Loot, Slay Monsters, Explore Dungeons, Repeat. If you have played Diablo, Titan Quest, Fate, etc. you will be familiar with the gameplay. It's not revolutionary but it is delivered in a polished package that is extremely hard to find any flaws in.
The game features 3 different classes to choose from each with their own skill trees, as well as choice of pet. Your pet begins as either a Cat or a Dog, though you can change them by feeding them fish. Once you start playing you will be hooked as time flies by always wanting to finish one more level. The game doesn't force you to play any longer than you want, exit at any time and you will simply resume from that location when you return.
The game runs well on even modest systems and laptops, Is available online as a Direct Download from the Torchlight website, Steam, and various other Digital Distribution Services.
When you download the 300 MB Demo you get the complete game, which is time limited and for a $20.00 purchase you receive an Unlock code to allow you to play the complete game. No additional Download required.
Later this week the Editor tools will be provided for download to allow the Modding community to create their own levels, and content which should lead to even more value in the game.
With most games costing $50-$60, I highly recommend you download the torchlight demo and I think you will be happy to spend the small sum of $20.00 for game you will get a lot of enjoyment out of.