I've been through a lot - MX510, rejected the 518 flat out, the G5, G5SE, G9, G500, Deathadder, Apple's wireless and USB mighty mice, but here's what stuck:
The Steelseries Ikari, and the Razer Orochi (laptop mouse).
The G9 needs a better location for the sensitivity switch and the scroll-wheel mode on top, the G500 needed profiles. The Ikari is simple by comparison - four buttons, click wheel, and two sensitivities… but the devil, as they say, is in the details. The ergonomics are glorious, and the sensor, noise correction, etc. are adjustable and do all their work on hardware - I just set the profiles, and forget the drivers ever existed, making them very Mac friendly. They're very accurate, smooth-tracking, and the switch feel is excellent. There's one button to toggle two sensitivity levels, meaning there's very little to think about while using them, and they're well placed to use without reaching, meaning you actually use it instead of ignoring it because of its accessibility (or lack thereof).
I'd like to like the Logitechs, but they offer a painful compromise with each new iteration.
I'd like to like the Razers, but their mac drivers kinda sucked - to the point they were performing better without them installed. The Orochi was the first exception, and the bluetooth/USB hybrid design was a nice touch.