If I had to choose just one I would need medication........

I guess the ones I tend to lean toward keeping are hotrod builds, and my "flippers" are rescue, rebuilt, release machines.

I have a couple of keeper bikes that are stone stock original, although the Campy bike is getting early almost period correct brifters. I do tend to keep original parts so I can return a bike to it's original state if need be.

The odd thing is, I also restore, collect, and race vintage Euro Off Road motorcycles. I wouldn't dare "modernize" one of them in a restoration unless something was simply unobtainable. I would first try and find a period correct aftermaket upgrade first.

The lack of readily available, and affordable, decal sets tends to make restoration a 2nd choice for some bikes. The decal set costs more than the bike in some cases.