Unfortunately we have lost some good builders over the last few years, including Estridge (which only is doing custom homes) and Davis, which also was a quality local builder. David Weekley Homes entered the market earlier this year and has taken over a lot of the Estridge neighboods. In addition to Pulte, Ryland and Fischer, M/I Homes and Drees, both have nice floor plans and are in good neighborhoods in your price range. Centex is now part of Pulte. Your best bet is to work with a real estate agent who has experience with builders and understands how to negotiate on your behalf. Like others have mentioned, it will not cost you more to work with a real estate agent. In fact, you're likely to get a better deal when you have someone looking out for your best interest. Builders are not going to give you a better price if you don't have a real estate agent. Most builders pay real estate commissions from a completely separate budget, so it's not factored into the price of your home.
In addition to looking at models and floor plans, I also recommend going to exisiting neighborhoods to see how homes look after five, 10 or even 15 years. Again, your real estate agent can help you identify neighborhoods for you to look at.
Good luck. Always happy to answer questions if you have others.