1. Snakes- by far the easiest pet to keep once you get the caging requirements cared for. Quiet, feed once a week, clean once a week (maybe twice), check water bowels every other day, and no allergies.
2. Cats- can handle a couple days left at home alone. They are entertaining (though occasionally destructive), loving, beautiful creatures with a mind of their own.
3. Fish- the fun is in observing them. Again, once you get the tank stablized, just feed and do water changes regularly.
4. Lizards- you must get the caging right or you're in for problems. Most require daily or every other day feeding. Some can be very personable and do seem to recognize their keepers. Entertaining to watch.
5. Parrots- I love them but I can't keep them due to my travel for work. Need daily attention! Varieties of food, toys, time out of the cage, lots of interaction or they go psycho.
6. Ferrets- neat critters but need more attention than I think most get. Can be hard to housebreak and require baths to cut down on the funky smell. Must be closely monitored while out of their cage because they go looking for trouble.
7. Birds (Non-parrots because they have different requirements)- I've kept various birds like finches, quail, small song birds etc... and though they don't require the personally interaction that parrots do, they can be entertaining to observe and the ones that sing add that to your home. Nothing like a quail crowing at 3 in the morning in an urban apartment to confuse the neighbors.
8. Rats, Rabbits, other small furry animals- can be good pets. I've enjoyed keeping rabbits in the past and rats are pretty smart for a rodent. I really don't like hamsters or guinea pigs though, just a personal preference.
9. Turtles and tortoises- aquatic turtles require clean water and so a powerful filtration system and regular water changes are a must. Tortoises live a very long time and I'm not willing to commit to an animal that may out live me.
10. Dogs- so why are these at the bottom of my list? I love dogs, especially the big ones, and I've seen way too many mistreated. I just don't think a lot of the people who get dogs should have dogs. In my opinion, a dog is like a child that requires nearly constant social interaction. People get certain types of dogs for reasons like protection of property and for social status. I wish there were a qualifying test for people considering getting a dog. Breaks my heart to see a pitbull or a rottweiler on a chain in someone's back yard.