We raised guinea pigs growing up. They loved to be cuddled and they do get lonely. The Humane Society actually recommends that if you are going to get one, then get two because they are lonely creatures and prefer company. Of course unless you want a bunch of them, make sure you get two of the same gender.
If you decide to get a hamster, they like to get out of their cages during the evening and run around in a different atmosphere. They like to sleep most of the day. The Humane Society recommends that you never put them in an exercise ball, especially if you have cats. Both types of animals can get stressed.