I may be in the minority on this, but I really hate it when I pick up a comic based on the cover and the interiors and the story look nothing like it. There were a couple of books today that I has special ordered from my retailer. When I sat down to look at them, they had very stylized covers. Then I opened the book and the interior was completely different. The art was more "sketchy" looking and had a ton of darker panels, while the cover was sunshine and light. It really threw me for a loop, and it made me not want to read the issue.
Once I get past this, I am usually alright. One of my small exceptions to the rule on this is Catwoman, which features Adam Hughes covers and David Lopez interiors. I think it is because I know what to expect, so it doesn't make me upset. I wouldn't mind though if Lopez did the covers, because I enjoy his work.
I sometimes also think that the interior artists should be allowed to get the cover dollars after doing a great job on the inside. It helps make a person a "star" and gets their work out there. My exception to the rule is on variant covers. I think that in this case, the interior artist should get one and a featured artist should get another. I am okay with that. Though I am not a big fan of variants, I at least would like to see the interior artist get a shot.
My other pet peeve is when the cover has nothing to do with the story. There are some silver age books that were especially bad, and though they make me laugh today, I remember buying comics on the newstand in a hurry because my mom was grocery shopping and then getting home and being disapointed. Those were the days. It doesn't happen as much now, since many covers are more "posed" then story driven, making it almost impossible to rely on the cover to tell the story.
Like I said, I am probably in the minority, but I really enjoy an issue that features the same art team from cover to cover. There are exceptions to the rule, but for the most part, it is what I prefer.
What do you like? Do you have a preference?