Plenty of good advice, so far. Lone Ranger pretty much nailed it. Your choice will depend on how you plan to use your revolver. Plinking and target shooting? Cowboy action? This will have a bearing on potential choices. If you're looking for a straight-up, Colt clone, Pietta and Uberti are good choices. Either should suit you well, including cowboy action(Guns are used a lot, in this sport...so use has to be considered as part of your long range plans). I have firsthand experience with all revolvers described below.
In my opinion, Pietta, is the best value in a modern, Colt-style single action revolver. Pietta's quality control has really improved, over the last few years. With the introduction of new, state-of-the-art manufacturing equipment, and strict quality control. Pietta revolvers are also the closest internally and externally, to original Colt single actions. Pietta parts, both factory and aftermarket, are readily available, here in Canada. Plus, the U.S. Rusty Wood Trading, for example...a site sponsor, stocks a good supply.
Same goes for Uberti. Very high quality revolvers. Some folks complain about the inclusion of new safety features in the new Uberti revolvers. Including: transfer bars, retractable firing pins, etc. Citing dependability issues. True, the more complex any machine is, the more likely it might break down. But, I personally have seen no such failures, to date. Uberti revolvers work like they should, even with the new features. A bit pricier than Pietta. But, still a good value in a single action. Lots of parts available, too.
Many shooters, including myself, consider Ruger revolvers to be the Cadillac, of single action revolvers. Very strong, durable, reliable. Capable of very hard use. The choice of many top ranked cowboy action competitors. If your preference runs to a traditional, 'cowboy'-styled revolver, the New Vaquero is a good choice. Available in a variety of 'cowboy' calibres. Pricier than either Uberti or Pietta, though. New...these revolvers will run around $1000. Still, a good investment. If you like guns that will easily outlive you.
Next: Ruger Blackhawk. Long considered by many to be the one of....if not the best... Ruger single action made, these revolvers continue to please their owners with excellent build quality, adjustable sights, great handling, pointability and accuracy. As I recall, the late, great Elmer Keith had a hand in designing the Blackhawk. Many of his practical suggestions carried through in the Blackhawk design. Though not purely 'cowboy' in looks, these revolvers are widely used in cowboy action competition. Blackhawks can often be found, both new and used, for well under $1000. Also available in a variety of calibres.
As already mentioned...Do your research...Before making any purchases. Hope some of this info is useful.
Al