I thought of this topic while I was re-watching some of "The Beginning" documentary on the Phantom Menace DVD. Ewan seemed more than happy to be in Star Wars at that point (although, like others have mentioned, it is like 8 years of their life). I do get a little tired of some of the actors moaning about how much they hate Star Wars now, or regret (in a way) being a part of it. Granted, some of their comments might not have even happened - or are taken out of context - but we know that some have repeated it on numerous occasions. We all know that Star Wars isn't Shakespeare, but isn't ok to just be part of a "fun" movie in your career? For all the grief he gets, someone like Hayden Christiansen seems to be a good sport about it. Whenever I have seen him interviewed for other work he's done, Star Wars inevitably comes up (especially lately with Jumper), and he always says how happy he is to have done the movies, how he enjoys children coming up to him and asking him questions, and things like that. If its not your favorite work, that's fine, but for many to most of these actors its their "biggest" work, probably some of the best paid, and certainly one - if not "the" - best known movie(s) of their career.
I noticed, around the time of the 1st OT DVD release, and now with Indy, that Harrison Ford seems to have backed off his bashing a little bit. He seems to lean more towards the "opened a lot of great opportunities for me" and "George is a great storyteller" type of comments. Natalie Portman has been pretty careful about her words as well that I've seen, and often mentions how she is happy she did the movies. I sometimes hope that this McGregor comment was incorrect, because he is probably my favorite character in the prequels - and did a good job I thought - hopefully he is more thankful for the part than this comes off.