BMW F850GS, R1200GS/GSA, Africa Twin, KTM 1190 Adv, Husqvarna 701, KTM 690, Yamaha Tenere, Triumph Tiger.
It really depends on whether you want more dual-sport or more tourer with dual sport ability. The best "middle of the road" all-rounder would be the Africa Twin. If you want a tourer that can do off-road no problem, go with the BMW R1200GSA. If you decide to go the route of the BMW, try and work in test rides with both Air-Cooled (pre-2013/14 models) and water-cooled ones. They have some pretty different power characteristics. My current go-to adv tourer is an 2013 R1200GSA--the last of the air-cooled ADVs. 1k+ mile days are no problem on it, I did an "Iron Butt" literally on a whim just to check it off the list, likewise it makes dirt/gravel touring and anything less than straight singletrack or soup-thick mud/muck pretty manageable. In those conditions, the weight of the bike can be an issue.
You can find A TON of info on any specific bike you might be interested at www.advrider.com. Enjoy the switch!