Bolt, G-Force, and Over the Hedge were favorites of my ds... All three are animal based and my library system has them. They are a little older so the kids might have missed them the first time around. I think Bolt would be my top choice for your age range. It's a little cleaner and innocent.
Bolt is about a dog who is a movie star but he is kept on the set all the time and he thinks he really does have super powers. He escapes because he thinks his co-star, a girl, is in trouble. He ends up across the country trying to get home. It's funny seeing how he rationalizes it when his super powers don't work in the real world (styrofoam must be like Superman's kryptonite!) and sometimes he does things that work out from sheer luck. It takes him a while to realize he isn't really a super dog.
G-Force is about hamsters (and a mole) who are spies. They've been equipped with a gadget that allows them to talk. The lab where they live is shut down and they get put in a pet store. They get adopted and have to escape their new homes to stop the evil guy. This one is a little more worldly, maybe not the best for the younger end but I suspect most mainstream folks would think it's fine for 5 yos.
Over the Hedge is about animals who wake up from hibernation to discover a housing development has been built over the hedge. A new animal in the area shows them the ropes of dealing with humanity. He stole some food from a bear at the beginning of the movie and is tricking the other animals into helping him replace what he stole because the bear threatened him. Happy message at end with the other animals telling him he shouldn't have been deceitful, they would have helped him, family sticks together.
There is some website that give a ton of details about movies. It's really great when you have a sensitive kid and want to avoid certain things that most reviews or other parents wouldn't think to mention. Let me see if I can figure it out... Ah here it is - Kids in Mind. Here is there review for Bolt. You can put the other movies in the search window. http://www.kids-in-mind.com/b/bolt.htm
Oh, we liked Planet 51, too!