A guinea pig for sure! I have only had mine for about two months... but I love her dearly. Contrary to some, I would say a guinea pig requires a lot of care. You need to clean their cage (I clean the dirtiest parts every other day, and the whole shabang once a week). They need fresh veggies and hay and pellets every day, some time to run about, and fresh water. Also, since guinea pigs can't produce Vitamin C. they need to be given it through food, veggies, and drops in their water. Most piggies love to snuggle and burrow in your arms. I have to say, mine has peed on me a couple times, but I solve this by always holding her on a towel. They really are cute, and make adorable noises! My guinea pig loves to be held, but I admit she is easily scared. Although, she does stand up to my dog, so who knows!
I can't say I don't like rabbits a lot too, though. My friend has a few, and they are very sweet and fun, I just prefer my piggy!