Don't get a Glock, just buy another USP barrel along with extra mags and a buttload of quality ammo for plinking and defense. The Tactical comes with a non-suck trigger already installed, so you don't have to worry much about the internals. The only aftermarket parts I would consider adding are tritium night sights by Meprolight.
I have big, goofy cartoon sized hands, so the USP Tactical in .45 was the answer for me, too.

