Each person is different and each person will have their likes and dislikes. She should handle a number of different guns, in different formats, and see what she likes. A woman is no different than a man in this regard. Her hand will fit some guns well and will not fit others. Go someplace that has plenty of guns and let her browse and take her time. Once she finds a grip that she likes, then consider what caliber. Each caliber has its own signature recoil (9mm snappy, 40 snappier, 45 push, .380 fairly snappy as well...). You may be surprised that she likes one caliber the best, and it may not be the one that you THOUGHT she would like.
It's her decision, let her make it. And, give her the tools to make that decision the right one. First make sure she has looked over this site...
http://www.corneredcat.com/
Then, take her and let her get touchy-feely with them all and find out what she likes. Then, before buying anything, go to the range and rent that gun, or a similar one in the same caliber. Then, get online and read up on the reliability of those particular guns. The following sites are good for that:
http://www.thefiringline.com/forums/
http://www.thehighroad.org/
And, of course, you can ask your friends here on Taurusarmed.net. Be aware though that although some guns get a bad review, this can be a matter of brand snobbery. Read between the lines on all reviews. Did the poster actually OWN the gun, or is the problem heresay? Did the owner try to correct the problem through cleaning, or did he/she just blow it off as an inferior design?
Either way, for a carry weapon, make sure it:
1) is reliable
2) fits her hands and carry method
3) is of an appropriate caliber for defense.
Once she makes the purchase, put in plenty of range time to get her acquainted with it, and also to make sure that it is 100% reliable. If it is not reliable, send it back to the manufacturer or have a gunsmith look at it.
All of the above is adviseable for ANY person buying a gun, not just a woman. I hope this helps.
Todd