Best Mid Range Mount
Sky-Watcher EQ6-R PRO Go-To (Wobble 0.6 arcseconds)
This is the best mount on the market right now in terms of performance/price ratio. The EQ6-r is a kind of frankenstien of the NEQ6 with a bit of the AZ-GTEQ6 thrown in. The result out of the box is a significant step up from anything that has gone before in its price range. It can carry and image with much bigger scopes than I am recommending here. If you buy this mount it will serve you well for years to come. BTW the older EQ6's can be tinkered with to be as good as this mount (and you can purchase a Rowan upgrade for the old EQ6's too) so if you see an old EQ6 second hand its a good option.
Sky Watcher HEQ5: Wobble whilst guiding less than 2 arcsecs (with rowan belt upgrade about 1 arcsec) Annoyingly its hard to get the Rowan belt upgrade in the states but if you are willing to do some tinkering and tune it up by following astrobaby's advice the standard HEQ5 will outperform the AVX. And if you decide to upgrade with the Rowan belt mod upgrade then this is a significantly better mount than the AVX. (FYI: FLO offers this mount with belt mod already fitted).
Celestron AVX GOTO Mount: (Wobble whilst guiding 2 arcseconds)
This is the modern upgraded version of the Celestron GT mount I used in my Astrophotography Shootout: £600 vs £6000 video. Like the GY the AVX suffers from backlash although thankfully not as much as its predecessor. The AVX is lightweight and has an excellent goto system. Its great for observing and planetary but it just doesn't quite deliver accurate enough guiding to use the AVX for deep space astrophotography with telescopes that have a focal ratio longer than 650mm.
... in 3rd Place
Note: I'm not sure where you can buy the Rowan HEQ5 belt mod in the US - sorry -
if you know please tweet me!