andrews10,
I agree with J.Baker with the following addition. I'd lean towards either the MKI or MKII, if you can find a used one that is. The MKIII's have been a bit more problematic than either of it's predecessors.

I'm an avid Bullseye shooter and own and shoot a multitude of High Standards, Marvel conversions, and a few Ruger MKII's. I Ransom test every one of them with a variety of target ammo, and have yet to find one of the MKII's target models(I've tested over a dozen) that won't group at 2" or better at 50 yards with any good target ammo (not the best target ammo, just good stuff). Usually it's in the area of 1-1 1/2". My best shooting has always been with the Rugers, albeit they have all had trigger jobs. That's the only modification I insist upon.

As J. mentioned there's a bunch of aftermarket stuff available, but as I mentioned the trigger should be addressed. If you're not shooting 100's with a Ruger, you can't blame the pistol.

Stork
Distinguished Pistol Expert#1298