Roger Ebert explains why he hates 3-D in movies. I don't like 3-D, mainly because it puts me to sleep…and if it's not adjusted perfectly, it gives me a headache. So that's my reason for not liking it, and since that's enough of a reason, I never stopped to ask myself if there's any case to be made for the process. Does it add anything besides gimmickry and higher-priced tickets? If it does, I haven't seen an example so I suspect Ebert's right on that point.
Still, I don't have quite his emotional rage on the topic. This may be because I don't have a job that pretty much requires me to see every movie that comes out.