Well, it not quite as bad as asking us to pick a wife; but, it depends mostly on what you want it to do and what feels good in your hands.
3 factors, cost, power, and handling. Don't skimp on value or quality (used guns are often good values) but you will want to keep cost down, you may need to revise your decision.
There have been many discussion (arguments) on minimum power levels but for the sake of argument I'm going to say that 45 ACP, 45Colt, and 357 are minimums and on up to what ever you can handle. I've had Ruger Superblackhawks and S&W M29's. they are always accurate but painful and expensive to shoot enough to keep on target.
I'm fond of 6" medium Frame 357's, Govt Model 45's and a S&W 625-8 that seems to know how to hit what I want to hit. For me, accuracy is a function of how much I practice. Most guns are way more accurate that I.
I had a Ruger New Vaquero in 45 Colt; but had to sell it to pay the rent.
My advice is to go to a gun range and try all the guns and choose the one that has the best balance of power, cost, and handling