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