You can currently get a D5100 body for about $450, the newer D5200 is not available yet--it was just announced a couple of weeks ago. But body is estimated to run you approx $1100 sometime in December. a D7000 body is $1000 (amazon prices)
a quick google provided this:
"The D5200 offers a 39-point AF system for smarter focusing and tracking of moving subjects (compared to the 11-point module on the D5100), a 2,016-pixel RGB metering sensor (whereas the D5100 judged exposure based on just 420 pixels), and a new Expeed 3 processor that permits up to five shots per second (versus the older camera's 4 fps). There's also a brand new main image sensor: a DX-format chip that is the same size as the D5100's and yet somehow squeezes in 8 million more pixels, bringing the effective resolution to 24.1 megapixels."I have a D5100 and it's low light images are really good It is better than the D60 (I had a D80 which has the same sensor as the D60) And the D5100 focuses fine-- the lens factors into this as well
Consider that the image files sizes will be larger since the D5200 is 24 MP…D60 = 8MP, D5100 = 16MP, D5200 = 24MP and D7000 = 16MP. Also, the D7000 is a larger camera than the D60 and D5100 series, so that should be considered as your wife may not want bigger/heavier.
Lots and lots of D5100 here samples for real world image quality references:
http://www.flickr.com/groups/nikon-d5100/pool/
