Games
Mercenaries 2 - Ugh... it was just plain boring. I really wanted to just play coop with buddies but by the time I got it my friends who played it played something else I forgot what come out after.
Street Fighter 4 - The existence of Super Street Fighter 4 >_>
Modern Warfare 2 - Nothing too wrong about it, I was just expecting a more balanced and less broken MP experience
Guitar Hero World Tour - What a broken system
Viva Pinata - It wasn't my thing, but I wouldn't be even half as mad if it wasn't for the hype behind it
Too Human - Thank God I didn't buy it :B

DLC
Way too many songs on Rock Band - mostly broken charting, difficulties, or the bands are the issue. I mostly just buy songs without thinking =\
Halo 3 map packs - I got Halo 3 ODST short after, rendering the purchases of the map packs useless >_>
Soul Calibur IV Darth Vader - No one at home plays him, and I didn't really like him, I prefer using Nightmare =\
GTA Lost and Damned - I bought GTA complete on PS3 >_>

That's just nitpicking imo