I have an original late '60's Peugeot PX-8 (French model...basically a UE-8 with a different rack and pump peg) in marginally better condition which is my "commuter" bike. I never ride it because when it is nice, I ride one of the "nice" fleet, and when it is crappy, it is snowing. I see lots of room for fenders, etc, perhaps I will dump the Peugeot. I think the stem goes (probably e-bay it to fund the project...I traded a ball point pen for the bike), seat goes, brakes probably go if I can find better center pulls with super long reach, cranks may stay. I think I am going to stay with the Huret derailuers. They still work great.
I sticking with the tubular tires though. I have been riding them alot more this summer than I have for years, and I like the way the ride better than the hi-perfromace clinchers on some of my other bikes.