Just to add a couple of ideas--I just went to the QuiltCon show here in Austin and although I don't need a new machine, I love looking at them at the shows. I've always been impressed by the light weight of the Janome Gem machines and they look very sturdy and capable for a small lightweight machine. I do own a Featherweight that I don't use (inherited from my grandmother) which to me seems extremely heavy for its small size in terms of taking it from place to place.
For your wife's gift, I'd be sure to check Amazon for the best prices from online stores. Though it's nice to buy a machine from a local dealership in terms of future service, you really can get the best deals online. Be sure to get a machine with an automatic threader, whichever one you choose!