This game is wonderful. Released back in 2002, I learned about this game through a cousin of mine, and I fell in love with the game. Spending well over 500 hours into its singleplayer and online multiplayer (now defunct -- LAN works great though), I never realized how much I would come to miss this game.
A classic dungeon crawler where you're not limited by classes or levels. You can be whatever you want, a pure melee character, an archer, a mage, a combination of two, or all of the above. You have the ability to choose how you level up your skills. Instead of levels, there's strength, dexterity, and intelligence. These act as your levels towards what you want to use in combat, and progressively increase through combat. This is different from the timeless classic of Diablo 2, however has a great leveling system that's sure to let you play however you'd like. The storyline is wonderful, and with co-op multiplayer, it adds on more difficulty so your not running around finding too easy.
Unfortunately, this doesn't come included with Dungeon Siege: Legends of Aranna, but if you happen to have a copy, you can install it over Steam's installation (plus with a little renaming of game executables) and be able to play it through Steam.
One of the downsides is that since its been over 11 years that Dungeon Siege has been released, multiplayer is now defunct. In Dungeon Siege, you'll find that the Multiplayer button gives you the message "Disabled". Is all hope lost? Of course not. By adding the launch parameter "zonematch=true" to your game, you can access multiplayer LAN and direct connection games without the use of warez, cracks, or patches. Its a shame that you need to bypass that message just for direct and LAN capabilities, but it gets the job done, and it still works perfectly.
I would definitely recommend this game for anyone who's a fan of dungeon crawlers, especially playing them with friends, and for those who are looking to try something new. It's not hard to get the hang of, but it won't get too easy on you either.