Best revolver? As in for a particular use? Most well made? Most consistently accurate (by brand/model)? Most well fitted? Most well finished? Most easy to shoot well? Most powerful? Most durable?
A lot of variables here to affect someone's perception of "best".
Fitting the most criteria in first place (excluding specific uses) and finishing in the top 5 in any of them would probably be a Freedom Arms Model 83. Followed closely by the Freedom Arms Model 97. These two are particularly good in the single action category.
If double actions are to be considered, then the prize would probably have to go to the Korth (although the actual performance does not justify the extra expense) as they are evidently amazingly well made. For us mere mortals though a Colt Python, Colt Anaconda, S&W N frame or L frame revolver would probably get the nod.
Had I to pick but one to cover as many bases as possible it would most likely be a Freedom Arms M83 in .454 Casull, premier grade, with a spare cylinder in .45 ACP, octagonal barrel (pure cosmetics...), and I would specify a 6.5" length if they would cut it for me in that length. Of course my bases covered are primarily concerned with outdoor and recreational use, as I am an auto-loader fan when it comes to self defensive side arms.