Prism gives some good advice. Also check out major quilt shows and give different ones a "whirl" so you get a feel for them. It might be worth your driving to the shop that rents time on a machine and trying a class--some people do not like the quilting process as much as piecing and it's a big investment to find out that you don't like it!
Also check with any "local" dealers and see if they have any trade-ins that might be of interest.