RE: 10mm or 45acp
If a .45 auto and a 10 mm are the choices, I'm taking the 10 mm. It's a bit more powerful than a .41 Mag. in the common loadings. Ammo availability is something to think about, not that many places carry it these days, but there is always mail order to fill that void. Ammo for 10 mm is pricey, but so is any good, quality .45 auto ammo too.
If I were buying a 10 mm, and I hope to one day, I'd get a Glock 20 with the 15 rd. mag.