What pistol I shoot best, and what pistol I enjoy shooting the most, aren't quite the same thing. We'd also have to establish what "best" means.
For best accuracy, probably my Ruger SBH Bisley conversion .44 Mag with a 300gr WFN load using 2400 running around 1100fps. It seems to be a particularly accurate load for me, though that's still not saying too much.
But if "best" means consistent hits on target at a reasonable speed, it's probably a G22 w/.357 Sig match grade barrel (after some recent changes to the trigger).
As far as favorite goes right now, it the relatively new G20. I'm really enjoying running drills with it using some mid range reloads.