Will be checking these out, thanks.
For Titan Quest, 1) get the Gold edition with the expansion pack, 2)make sure to get the community patch. I also recommend the TQ Defiler (it's a 3rd party utility made by fans), it comes with some tweak mods (such as potion stacking). Once you beat the game on the first difficulty level, you can go back on higher difficulties to get better loot (creatures are leveled up to you on the re-plays, so they are still challenging) and continue leveling your character. Special bosses also appear.
For LoK: Defiance - you don't exactly become god-like (certainly not as much as in the other games I mentioned)... and the game does have its flaws (mainly, the camera is probably the hardest enemy in the game). However, the story and character development are really amazing. It's the last game in a series that started at the PS1 era. The game manual provides a synopsis, but it is kind of easy to lose track of what exactly is happening, especially since there's some time travel going on. There's a lot of fun puzzle solving, too.
In Rygar... I guess you never become super god-like, but you do pick up two new weapons, and you can find various power stones that give you special skills and buffs. Laughably bad voice acting, but the soundtrack and graphics are awesome. The boss battles can be wicked tough, though.