For visual I'd go with the Lightswitch. An 8" SCT on an altaz mount is soooo comfortable to use. I'm not too concerned about the Lightswitch part; nice if it works, not needed if it doesn't (you can always do a manual align of the Autostar).
Imaging I'm not too sure. You might be able to do basic imaging with the Lightswitch, but it really wasn't designed for that, and this is coming from someone who has imaged with an ETX-60 (and enjoyed the challenge). You might contact Rigel123, he has done some very impressive imaging with an Lightswitch 6(?).
The 120ED is a nice scope and I do luvs my EDs (80 and 100). I'm not so sure about the LXD75. I have two LXD75s and the LXD75 was my first 'real' imaging mount. By today's standards it is a fairly lightweight mount and needs a bit of TLC to work well. I currently use one of mine with a pier extension and a Meade AR6 6" f/8 achromat. It works well for visual and I have done a fair amount of imaging with it, but again, by today's standards its kinda rough, on-par with a CG5. Also, as much as I love my refractors, the eyepiece swings through such a large volume of space around the mount that for me they aren't the most comfortable scope to use. Soooo, I'd be happy with the scope, not so much with the mount (and I like the LXD75!). My LXD75s now serve primarily as lightweight visual and EAA mounts. I'm looking at moving the AR6 over to my Atlas.
Sooooo, if'n it were me I'd take a hard look at the Lightswitch as a general purpose visual scope that is capable of basic imaging, or the 120ED as a visual/imaging scope and look at upgrading the mount to something a bit heavier and a bit more modern when I got the chance.
Food for thought.