Aaron
If this is your first S&W 45 ACP revolver then I recommend either a Mod 25 or a 625 deppending on whether you want a 6" or a 4".
I started using a S&W Mod 25 in the early 1970's. A 45 ACP revolver is an excellent gun.
For your first one I would want a steel frame with adjustable sights, regardless of barrel length.
For your second....
A few months ago I got a 325 NG, I am wearing it now.
I really like it, it is very light, plenty accurate, and since I am fully versed with full moon clips VERY fast to reload.
IMHO, IF, you do not need the POWER of the 44 Magnum, then a 45ACP revolver is a great choice.