Although 1100/1200's are dependable, Joe is right about 1500's. Lots more parts available and interchangable between years. The 1500 was made for 13 years and is pretty much free from major problems. The 1000/1100/1200's were only produced a few years each and maint is much harder to perform on them. Now is your really handy with a wrench, have time and have a good shop manual, then they can be a bargin. Good luck and ride safe...
I love the look of the 1100, kinda of like the future waiting to happen past tense. My dealer tells me "you can't get parts". Hey don't ride on luck. I would get a 1200 over an eleven, clean w low miles. Parts may still be a trick but easier than an 11.
Never fear parts for older Wings can be found and while they may not be new they will keep your bike running. Try www.usedgoldwingparts.com for you old Wing part needs.
Personally I wouldn't want to ride an antique motorcycle, I'd rather put it into shows. Oh yes, I am looking for a special older Wing the 1976 Limited with the gold wheels. I almost had one a month ago, someone else knew what it was and got it before me.