I have a KelTec PF9 (two of them actually) and it's a great little gun (single-stack 9mm, 7+1). It carries in summer shorts like it's not even there. It does, however, need a little feed-ramp adjusting to load hollow points consistently. The P11 is also a fine little gun from KelTec, though I don't currently own one.
A Cobra CA380 made it's way into my possession at one point. Worst gun I've ever had the displeasure of owning. Stay away from Cobras!!!
The Ruger LCP (380) graced my safe at one point. But I found 380 impossible to procure, so I let it go. It was a really easy carry gun with a snappy recoil.
Kahr also makes some fine guns. There are so many 9mm Kahr models to list...I won't start. Just go here
http://www.kahr.com/PA-1_9mm.html and take a look. I actually went to the gun store intending to purchase a Kahr CW9 when I bought my first KelTec PF9. After holding and firing both, I picked the KelTec. After my wife fired my KelTec, she tried to keep it, so I bought her one.
Take your GF to the range and rent a few guns. Don't make the mistake of looking a gun over and assuming it's going to be good for her. Good luck in your shopping!