I took my wife to the store and we walked out with a Ruger SP101 spurless snubbie in 357. She does not like having to rack a slide so semi-autos were out and she did not like the light weight revolvers. The Ruger fit the bill perfectly, it is fairly small, solid (read - does not feel like a toy), reliable, the price was less than $500, and it is Made in the USA.
This was already mentioned, however if you're serious about trying to get her to the range more than once, I would second the recommendation of checking out http://www.corneredcat.com/ It is geared toward women, but there is a lot of insight there that can be gained by men in your/my situation. I read almost everything on the sight and am very glad I did before I went out and picked out a weapon for my wife. Good luck.