Champions Online (got nerfed way too often) - 50$
Dawn of Discovery and Venice (bug ridden and boring) - 75$
Defense Grid (just boring) - 10$
Galcon Fusion (i don't even know why i bought it -_-) - 10$
Killing Floor (so atrocious that i couldn't even play 10 minutes without vomiting) - 15$
Mayhem Intergalactic (no one else is playing it... literally) - 10$
R.U.S.E. (shoddy acting, bugs, pathetic storyline) - 18$ (regional jewel, its cheaper than steam version)
Unreal Tournament 3 (don't understand, nor like it) - 10$
Democracy 2 (bored after 1 hour) - 20$
Assassins Creed 2 / Settlers 7 / Splinter Cell: Conviction (boring, boring and bug ridden, boring and abandoned by UBI) - 54$ for all 3 of them or 18$ each
Hammerfight (bug ridden, weird and ultimately - boring) - 10$
Stupid mistakes, lack of demos and misleading infos :/
This is nothing though, compared to some real $#%& that i bought and regret to this day:
Demigod (unplayable multiplayer, bug ridden, lack of campaign, beyond boring) - 60$
Battleforge (lots of cheaters) - 30$
Age of Conan (nerfed my character and turned out to be huge disappointment overall) - 100$
Guild Wars (no idea why, but i stopped playing two days after the purchase) - 25$
[drum beat]
Everquest 2 (wasted years, wasted money and nerves) - 1000-2000$+
EQ2 was both my first MMO and first multiplayer game, it was also the first time when i had to use credit card to pay for something over the internet. Without eq2 i would not have learned about Steam (or learned significantly later) and i would not have tried other multiplayer games either.
/sigh
Just remembered:
Conquest! Medieval Realms - 30$ Again - no idea why i bought it. Lacks proper multiplayer, boring as a result.