Tbone before you do ANYTHING cosmetic, and spend a bunch of money there, i would spend a little money on the mechanicals. List of priorities, IMO
First and foremost: Valve clearance check/adjustment. You'll chase your tail till youre nuts if you dont do this FIRST. You'll never solve carb issues, idle and off idle issues, hard starting issues if this isnt done. Its not hard at all on these motors, and either Dardoonk, or I, would be happy to walk ya thru it. I even have a fair collection of valve shims around if you needed that i would donate to the cause of getting another beautiful 8valve GS750 back on the road. You'll find these bikes are amazing for the age. Rock solid, handle like a dream, and they basically ripped off the Kawi powerplant design, including the bulletproof roller bearing crank. Seriously you have to intentionally try to damage the bottom end of these things.
Second, thorough carb cleaning, carb oring replacement, and intake oring replacement. All of these parts can be purchased at www.cycleorings.com for less than 15 bucks-ish. If you are sticking with the stock airbox and pipes, there will be no need for a jetting change obviously, but if you do decide to go with pods and 4into1 pipe, Dardoonk and i can give you a pretty accurate base for jetting for them. There is also an EXCELLENT tutorial with great pictures on thegsresources.com. That and the Stator Papers on there are must reads for this bike.
Third. Do yourself a favor and ditch the points and condesor ignition and get yourself a Dyna S and new Dyna 3ohm coils (the green ones) The total bill for those parts will run you about 250 bucks, but its WELL spent. You'll never have to dick with points again, and you'll get a nice fat hot spark to fire that mean motor.
Fourth. The one blemish on the GS design was the electrics. Namely, the Reg/Rec. They are crap. For 40 bucks, ditch that stocker and pic up a Honda R/R from Duaneage on the GSResources site. Just send him a Private Message. It comes ready to wire, he'll give you a diagram as to what goes where if you dont already know, and if you have any other questions, he'll be more than happy to assist. It may not even be a problem now, but nothing sucks worse than to have to push your bike home or leave it somewhere cause the charging system failed. Other than that, go thru your connections with some fine steel wool or a wire brush, clean em up, and give them a nice coat of dielectric grease.
Believe me, as i know from experience, these things will assure that your bike will more or less run forever with proper maintenence. There are guys on the GSR who have logged well over 100,000 miles on thier GSs with out rebuilds. They are that rock solid. Good luck and if you have any QandAs be sure to hit us up man!
Josh