Should I get mice, gerbils, or a hamster?

I don't know which to get. It needs to be easy to care for, not need a lot of time, not be aggresive (bite, scratch, etc.), not need too much out-of-cage time, and fun. I have two dogs, by the way, but I can keep them away easily. I don't have a lot of time with school and two dogs, so it's better if... show more I don't know which to get. It needs to be easy to care for, not need a lot of time, not be aggresive (bite, scratch, etc.), not need too much out-of-cage time, and fun.
I have two dogs, by the way, but I can keep them away easily.
I don't have a lot of time with school and two dogs, so it's better if it's easier.
Please explain why you think one is better, and give me some info about them (one or more, cage size, etc.)
Update: I've had mice before (though I was about five at the time--they weren't entirely my responsibility either) but I can remember that I didn't have problems with smell or sound. I don't know much about gerbil and hamsters, though.
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