My first suggestion is that you shop around and talk to dealers of several different machines. If you haven't bought a new sewing machine in a long time, be prepared for sticker shock! Consider buying a used, but reconditioned machine from a reliable dealer. You might be tempted to buy a machine from the Web, but top-of-the-line machines are sold by dealers, so you're taking a chance when you buy something on the Web. You'll need the dealer more often than you think, too! Keep reading.
I used to be a Singer sewer. In 1988, my 20+ year old reliable Singer died, and I bought my first computer machine - a Viking. I loved it. 10 years later, I switched to Pfaff, because of Pfaff's built-in even-feed - you really don't need to use a walking foot! If you've ever used a walking foot, you know what I mean. That alone is worth the money you'll spend on Pfaff's computerized machine. Viking still hasn't come up with something similar even though they bought Pfaff.
Don't buy more than you need. For example, if you're not into embroidery, don't buy an embroidery machine. I recently bought an embroidery machine, because I can no longer hand quilt, and there are a lot of great outline quilt designs available. I've had a hard time with free-motion quilting, though I haven't completely given up on it. There's a neat (and expensive) attachment that works with both Pfaff and Viking machines that takes the wrestling with the quilt out of free-motion. I can't remember what it's called, but I tried it out at a week-long Sit and Sew sponsored by my dealer. It's on my Wish List!
It really makes sense to find a good dealer. I've been VERY lucky to find an excellent dealer in Tucson. They've been in business a long time. They handle both Pfaff and Viking, and they're really into customer service. They give free classes when you buy a machine from them - as do most good dealers. This is very important, because the new machines are pretty complicated. The handbooks are good, but they're not a substitute for classes or a dealer who is just a phone call away. They also have Pfaff and Viking Club classes. Good dealers do this, and you can learn at lot from the clubs. I have a friend who has a similar good dealer in Santa Rosa, CA, so I know mine is not the only good one!
Another thing, good dealers invite well-known teachers to give 2 or 3 day or week-long classes (like the one I mentioned above)- another great way to expand your working knowledge of sewing. Good dealers let you trade up: My dealer gives a full-value trade in if you decide to trade up within 12 months. Hard to beat that! Finally, because they take trade-ins, they usually have older machines that they have completely serviced and reconditioned and sometimes even upgraded (which they can do because they're computerized), and they re-sell them at great prices. That's how I bought my embroidery machine. And even though the machine is several years old, I still got the free lessons!
I think you'll find that Bernina owners are just as dedicated to their machines as I am to Pfaff. I hope you hear from them, too.
Good Luck!
JoanneS