I have to put my 2 cents in for Bernina. I bought mine used. I got a full warranty, free lessons, and a quilt store discount for 20% off everything the rest of my life.
I have to second the advice to check out the used machines. My machine came from a woman who traded up to the newest 830 Bernina--we will NOT even discuss the price of that little beastie! My machine came w/ 8 hours of sewing time on the machine and 2 hours on the embroidery module.
Buy what you can comfortably afford. That way, you have no regrets.