.22 Rimfire? The most bang for the buck is a Ruger Mark II Target.... either a 5-1/2" bull barrel or a 6-1/2" tapered heavy target barrel. Add a Volquartsen sear, hammer, and trigger (about $100) and you have a VERY competitive pistol. The Mark II is out of production, so you need to hit the gun shows. The currently produced Mark III is a "lawyerized" version of the Mark II, and seems to be less popular.
Centerfire? I'm a 1911 fan... Kimber, Springfield Armory competition models, or an old Colt Gold Cup. If it ain't a 1911, I must plead ignorance. I've shot a bunch (Beretta, Glock, Ruger, Springfield XD....) but never warmed up to any of 'em.
I would have to agree The Ruger MK2 target is one of the best 22 auto's made. I have the 5.5" bull target model. I also have a MK1 tapered barrel target that is a great shooter. a 22 that I happen to like better is a revolver by S&W. It is a 617, 6", 10 shot, ss, target model. More $$, but for me a way to go back to the basic revolver shooting at targets.
Try the Glock 17 Gen 4 pistol. It is one of the best in the world. It is a semi-automatic safe action firearm. Or you can go for the Springfield XD. It is actually ranked 8th in the world. Well if you want the best then go for CZ 75 SP 01. I would recommend the Glock since you want it for practice.