Been there, done them...
Had '02 LT. '05 & '07 RT. Now '07 GT. I'm 6'4" and 265. Here's my take.
IF you're gonna do a LOT of "long" ride touring, one up, then I'd go with the LT. However, It's a little more than a tad top heavy and a handfull at parking lot/walking speed. I didn't like it for the majority of my "around town" riding and commuting and didn't do enough "long" riding. The weather protection is great.
The RT's were great for touring and playing in the twisties and with a little tweaking of the ergo's(bar up/back's, peg's lowered from Surburban Machinery) & Corbin saddle were all I needed.
The GT has to be THE bike for the "grin" factor. I'm getting used to the slightly more aggressive riding position with peg's lowered, tall OEM shield, bars UP. I'm gonna keep the GT as long as I can keep somewhat comfy with my arthritic knees. Then I'll have a decision to make myself.
As you have probably read elsewhere in this forum, it's an "to each his own" situation. This is true with all three.
I'm with you as far as the GS. I want a little more wind/weather protection. I would have one as a second bike.
To make a long story short. I would ride the wife's GT as much as she will allow. Then if the GT is not your cup of tea the RT might fit the bill.
Most important! RIDE all of them first before making a decision!