I personally like aquatic turtles a lot.

Here are some websites about owning turtles:

Turtle Times - Great turtle website with tons of information
Everything You Need To Know About Raising Healthy Turltes- Great website with tons of information on land and aquatic turtles/tortoises.
The Turtle Forums- Sorta like Pet Talk, except it's about turtles
Owning and Care of a Pet Turtle
Owning A Pet Turtle

You could also go to your local library and check out some books on owning turtles and tortoises.