Dungeon Siege Master Index
Try not to read ahead! This is a hugely fun game, and a lot of it is about how you develop your characters over time. Note that the walkthrough doesn't exactly follow the quests listed as you play the game. That's because many quests are "fake quests". For example, a quest given to you in Chapter 4 might not actually end until Chapter 7.
By far the nastiest chapter for me was Chapter 4. I just hated it and the swamp. Compared to that, the later chapters went VERY quickly and the last 2 chapters were super fast.