If Klingons are in the movie, don't put the TOS era ones... I think the TNG era ones had a lot of character and I think the younger generation connects to those more...
Most "non-Trek" fans are going to be like, "Why does that Klingon look like just a random guy with a painted face and big eyebrows?" or... "That Klingon doesn't look like Worf..."
I know die hard fans aren't going to agree with me, but I can really see this being an issue.