From the view point of someone that doesn't fully appreciate them, I've put quite a few on this past year. I found on chrome fenders they washed out the look on a yellow bike but were pretty nice w/o fenders.
Its funny, Im of the 60's era and I like a tire with a red stripe...
I put a pair of red stripe tires on a green frame Schwinn Cantilever w/o fenders and I thought it was the best look ever.
As far as looks go, I guess it just depends.
Originality is different though. I'm glad I haven't caught the original tire bug....