BenMcMichael said:
let me just say that a few of these games do not seem that under appreciated: phsyconauts, okami, beyond good and evil. Yes they werent the biggest selling games ever, but from what i have seen everyone on here loves them, they all got good reviews as well. So they may not have been marketed right but they are not underappreciated.
Apparently we have a different opinion on what constitutes "under appreciated". To me, it means "the mass public under appreciates the title", or IOW, the title doesn't sell well. 8 people on a forum does not the mass public make. Particularly this forum, which doesn't seem to be full of people like Yahtzee's "Adrian".
The OP didn't state what constitutes under appreciated. I'm going with "didn't sell well enough to make publishers justify continuing to make games like it".
So put me down for Evil Genius, Vampire The Masquerade: Bloodlines, The Longest Journey, and Startopia, in addition to my aforementioned Anachronox, Sid Meier's Alpha Centauri, and Beyond Good and Evil. Good games that not enough people played. I will admit, many of them had their bugs and design issues. But no one is perfect. The creativity of the titles and their storylines make them stand apart from more over appreciated, mediocre titles (I don't want to flamebait, but choose a platform exclusive with a number on the end and you wont be too far off).