RPG Vault has written up a preview of Titan Quest, based upon what they saw of THQ and Iron Lore's action RPG during this year's E3. A snippet to follow:
The character system seems to be pretty flexible. My understanding is that you don't have to select a class. Instead, you select the combination of fighter, spellcaster and rogue skills you desire. Since the designers don't plan to allow capping out in more than two, there should be potential for replayability. Adding to this, it will be possible to enhance abilities in different ways. As a simple example, you might want to maximize the damage output of your fireballs, give them the greatest possible range, or some combination.