Should have made a poll, man. I'm late to the party, too, but I'm thinking of picking up a Wii for my girl. If you're buying it partly for your girl you may want to consider simplicity of the controller. My girlfriend loves classic systems like Nintendo, SNES, and arcade games, so I think the Wii would be best fit if this is similar to your situation.
If I was buying just for myself I would go with the XBox just because of the price difference vs performance. I've played the XBox and PS3 on occasion and couldn't really tell that much of a difference in gameplay / rendering. (maybe I'm just not picky enough)
I hear that the PS3 renders distant objects better but haven't seen anything in person that convinces me that it is truly superior to the XBox.
All the systems seem to have a decent selection of games, but if you and your girl are going to play together, I would go with the Wii. If you don't plan to dedicate much time to playing / don't have a favorite series exclusive to one platform - go with the XBox.
If you plan to get into gaming as hardcore as before, go with the PS3.
That's just my long-winded, semi-inexperienced opinion.
Good luck and have fun.
Edit: Just noticed you said all you play is shooting games - then I would count out the Wii. Don't know if any of this helped, but in between PS3 and XBox I would choose XBox (and I've never strayed from the Playstation line)