I carry a G23 because it has no safeties. Much like in the movie blackhawk down, my finger is my safety. I've been through a bunch of live fire shooting classes and became very comfortable and respectful of firearms. Plus I'm just used to the glock it was my first pistol and I paid $409 for it. As far as ammo it eats whatever I put in it at the range so whatever is cheap when I hit the store I buy. For carry I use Corbon DPX do some reading at
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/index.htm to make an educated decision for carry ammo.
Ooh yeah and I wear an inside wasteband holster from Comp-tac.com it's the minotaur model.
http://www.comp-tac.com/product_info.php?products_id=95 If no one has said get a real no kidding gun belt too if you plan on wearing a belt holster. I got mine from
www.beltman.net custom made to order with a wide variety of options. I got a natural horsehide belt with a velcro lining (my holster is velcro clips instead of c clips). This combo allows me to conceal in a tshirt as long as it's not tight around the waist. My Tat shirt from NHC is an "athletic" cut shirt and it does not really allow for carry with out printing.