I like to have room for a slightly wider tire than some of the older racing bikes. I have a Peugeot and have to deflate the tire to remove the rear wheel. Not a huge deal, but not ideal.
I like to be able to ride on anything and not worry about curbs and cracks, so I ride a slightly fatter SOMA tire.
I like the peugeot because it has virtually no braze-ons, so it doesn't look like a frankenbike when you are done. When I rode it SS, I had nice clips for the rear brake. When I removed it, clips gone, brakes gone. The only residual is the holes for the centerpull brakes. No bosses for shifters, bottle, cables, etc.
I also like 120 spacing in the rear for track hubs. Looks clean.