Do yourself a favor and involve your wife in your decision.... as you have seen in the responses so far, every sewer has their opinion on what they think is the best, if your wife is serious a sewing she will have her own "wish list." What you can do is support here interest by taking here out so that she can compare a variety of machines, a quilting show or sewing expo is great for this. If you are in Colorado, there is a great show this weekend at The Ranch in Loveland... and DON'T rush into this... be patient. You may even be able to pick up a great used machine with more features.
IMHO

It just really depends on what she wants. I am also looking for a new quilting machine and I want it to have 4 things: needle up/down, automatic thread cutter, drop feed dogs and a large harp (opening). My husband wouldn't have a clue as to what to look for. You are precious for thinking of it, but I think I would let her pick it out, unless you are absolutely sure of the features that are important to her.

What about the Husqvarna Mega Quilter? It's right at $1000, pretty basic so that would help for a beginner and it's a work horse!! Hands down, that's what I would pick for your descriptions and price range. She will love it and use it forever I bet.
;) What an awesome hubby to support your wife's latest endeavor!

I have a Babylock Embroidery Machine that I love; however I am using a Featherweight machine to do a blue jean quilt. It sews through all the layers with no problem. I just love the way it sews.

You are a fabulous hubby to be supportive of your wife like this. However, let your wife make the decision about what kind of machine she wants - it may be completely different then what you had envisioned.
My DH was all set to buy a new machine one year because he thought I needed one. He enlisted our daughters to help him pick the machine and both said to him "Let Mom do her own picking so she can find the one she likes/wants/needs." It turned out that I am in love with vintage machines and none of the newer ones make my heart go pitter-patter so I didn't end up with a new machine but as new-to-me machine. DH said he would never have chosen one like that for me.

Chris

What a guy ! ... but I agree on having HER select a new machine ! She needs to try various models out and see what she likes best ...
That being said, my personal recommendation for a heavy-duty all-round GREAT sewing AND quilting machine is the Janome 6600. Hasn't let me down yet in 2+ yrs for piecing and machine quilting, and it sews denim, home decor, canvas etc easily. A workhorse but also versatile for all kinds of sewing. The 6600 is a bit more than $1,000 - probably in the range of $1,100-1400 depends on the dealer - but you get a LOT for your $$.

The older, electrics, like Singer 15-91 are good for denim. It has a vertical feed bobbin that can be used for free motion quilting. Denim is a once in a while thing and she will probably move on to softer, 100% cotton fabrics, which are the main quilting medium. The Janome Horizon, used by Leha Day in her videos is a great quilter because of the DUAL FEED system and the automatic thread cutter and needle threader. Dual feed keeps the fabric from creeping under the needle and it delivers the fabric at exactly the right speed to the needle. They list for over $2,000, but you can get them for a lot less now that a newer, more fancy machine has come on the scene. Personally, I would get a Janome of some kind, the best you can afford. The parts are more reasonable than the European machines. Attachments are readily obtainable. Whatever you do, please, get her a 1/4" quilting foot with the metal guide. It makes 1/4" seams more attainable without eye, back and neck strain.
Quiltmaker magazine, 30 year Halloween edition, has a chart comparing all the quilting machines. They are more toward the high end pricing, but you can see the features. Rather than suprise your wife, sit down with her and go over the features of various machines, so she can get exactly what she wants and you will be rewarded by her contentment with the rather large purchase. Good luck and thank you for being so thoughtful.

I agree with the folks who tell you to let her pick her own -- machines today have so many features, only she can tel you which ones she would find most useful. Be aware, many of the Brothers are similar to the Janomes, but they cost less.

When I need real heavy duty stitching, I haul out my Elna Supra (vintage 1976). When I bought it, they told me that it would go through anything if I used the correct needle -- and I even sewed through cardboard. (Is she using a new Jeans 18 needle to try to get through the thickness?)

I had the Janome 6500 and now have the 7700 -- love them both. I got the 7700 for the freearm and the better lighting, as well as accufeed. The 7700 sews through most thicknesses with a little encouragement, and is a dream for piecing and regular piecing.

In my opinion the JUKI 98Q or newer version is the best. I saw it sew through ten layers of denim in the demonstration I got that made me decide this was the one. I made a good decision. It works like a horse and never tires.

The Husqvarna Viking Sapphire 835 is within your budget, it has a 10" throat space and is great for machine quilting. I have the 875 and it has the same 10" throat, just more features and decorative stitches.