Before you purchase a tea pot, decide what size you need. If you only brew enough to have a cup or two, there is no need for a mammoth 12 cup capacity pot. If you often invite others over for tea, a single person pot and cup combo isn't going to work well.
How do you heat your water? If you prefer to heat the water on the stove and use the same pot for heating and serving, you need a metal tea pot. Those pretty ceramic ones are great for serving, but you can't heat the water up in them. Basically, you need a tea pot that is also a kettle, or you need a separate kettle and a serving tea pot.
If you brew mainly loose tea, consider a pot with a built in strainer. This way you don't need to fish tea leaves out of the cup after pouring. If you prefer bags, keep in mind that a bag can clog the spout if you don't remove them before serving. Choosing the right tea pot for your needs requires more than just picking out the prettiest one.