I've had 3 "K" series BMW's and 2 R100RS', the 1993 K1100LT was the best, a superb tourer, faster than a 'Wang and easier to move around at slow speeds, with incredible fuel economy good handling and ABS brakes.
The K series bikes here are generally cheaper than the R series twins, and in my opinion, much easier to live with. I wouldn't swap my current K100RS SE ABS1 (what a mouthfull!) for another R100RS, I was disappointed with both of them, although the later (post 1980) 1000cc twins were much better behaved, if not much slower.
GS Suzuki's are great bikes, I've had a heap of them, and the GS1000G (shaft drive) was a brilliant bike, fast, smooth, and bullet proof. I wouldn't buy an XS1100 Yamaha as the handling was terrible compared to anything else of the era, but the FJ1100/1200's are incredible long distance bikes, with 130 BHP, good brakes and good handling.
Really though, you need to take your wife with you when you start looking at bikes, because she needs to try them out to make sure that they suit her requirements. Happy wife, happy life........ Cheers, Terry.