Yeah, most definitely. The biggest offender was Halo 3 for me, I followed it pretty closely and even bought all three editions for some reason. Wow, what a disappointment. I guess I was expecting the story and atmosphere to be a little darker due to all the trailers. And there to be bigger battles as seen in the super bowl trailer. Ah well, it taught me a lesson.
After that was Fable II, not quite as bad but I'd knew literally everything about the game during the development because I was an Admin on a Fable II forum. I was taking everything I'd heard with a massive pinch of salt (Molyneux after all) but when I got the game I found it to be pretty shallow, with a pretty poor story. Molyneux is a filthy liar.
Anyways, as a result, I only really take in tiny snippets of games I'm interested in now, it's working out much better so far.
[small]Huh, feels like I've just spoken at an AA meeting.[/small]