The guys at GameSpot had the opportunity to get some hands-on time with the latest build of Titan Quest and have released an updated preview based on what they saw of THQ and Iron Lore's action RPG. An excerpt:
Even though the game will feature branching "trees" of skills, similar to the skill systems of Diablo II or Dungeon Siege II, the idea behind the skill system is to let players customize their characters by focusing on their favorite skills, rather than constantly outdating old skills by picking more-powerful versions. The low-level "fireball" spell you learn at the very beginning will continue to be useful through the end of the game, at which point you could have invested many more points into the same skill to empower the spell with more range, more damage, and other powerful additions. The game will actually let you reinvest some skill points as you go so you won't end up accidentally putting points into skills you change your mind about and decide that you don't like.