Eh, at least Assassin's Creed was trying something that was different, it was a great idea, soiled by poor design choice after poor design choice, but it certainly did present itself very well, there are worse games out there for sure.
I'd like to make another nomination quite honestly, and it's fairly recent.
Spore, I'm pretty sure that I don't need to explain myself here, but if I do, I'll say this, it didn't live up to the hype, it wasn't as good as Will Wright's The Sims, we weren't given anything we were promised, we were told that it'd be on a more epic scale, but instead, we get a wannabe god simulator ripping off 5 different games, which also happens to have an invasive DRM too.
So...Meh to Spore, I'd rather play The Sims thanks.