Most popular wetsuits brands are Tyr, BlueSeventy, Roka, Xterra, QR, DeSoto and Orca. Each of these brands have 3-4 models that start cheap ($200) and end expensive ($1200+).

If you have the funds, get a high quality wetsuit that is thin in the shoulders, as you'll notice a huge difference in the shoulders over long distances. Typically, thinner material is more expensive. I was able to find a Tyr Hurricane Cat 5 for about $400, and have been very happy.

Swimoutlet.com carries many of the top brands, and has good customer service.

If you are short on funds, you can always rent a triathlon wetsuit for an event from a local tri shop.