My recommendation is to purchase the best machine you can. Make a list of what's important to you, you know, which bells and whistles you need/want, share your list with the dealers, and sew, sew, sew until you find the perfect fit for you. Be careful not to let a dealer talk you into a machine that has way more functions than you will ever use; I believe thats when one over spends.
While it may seem expensive right now, it (a machine with a perfect fit for you)will last a long time. Also, take all the classes that are offered as part of the purchase. You'll be suprised at how much fun your machine will be to use when you know exactly how to use it. Seriously consider a used machine, too. There are some great 'older' models out there that have been traded in for a machine with more bells and whistles and I bet you can find the perfect one with your name on it.
I purchased my Bernina 830 (the very first issue) in 1973. In the 28 years I have had this machine, it has NEVER broken down. I have taken it in for cleaning, etc. about 6 times, and I replaced the cord for the first time just a few months ago. It is a full metal machine, and very heavy, but sews like a dream. Doing maintenance is quick and easy, so I can keep up with it. Hauling it to class is not a problem, it just takes a little extra muscle to lift it in and out of the car and on and off the table. The reason I said to buy the best machine you can: my machine is still exactly the machine I want, still fits my needs, and works like a champ doing exactly what I ask it to do so I don't even think about trading it in. I paid less then $500 for my machine, and if I wanted to (which I don't) I can sell it for almost three times the purchase price. Cool, huh?
There are many features that I love about my machine, but one especially worth mentioning: when you start sewing on the edge of the fabric, my machine doesn't shove the material down into the feed dogs even if I don't use a 'leader.'
The only downfall (for you, not me) is that the throat is 7 1/2". I don't long-arm so it is a non-issue for me.
You are going to use this machine a lot, so take your time and do your research, and lots of test sewing. Stay true to your expectations, and the perfect machine will find you.
Good luck!
Chris