I found this chart that recommends tire size and inflation pressure based on weight and terrain.

I appreciate your post, Scooby, and I had noticed the weight (of the tires) and was stressing about it before you posted. Unfortunately the 28c Supremes seem to be sold out.

Because of my experience I don't want to purchase Vittoria. Sorry I don't know which model I had. I tried to find out from Bikepedia, but it seems my bike was supposed to come with Hutchinson tires.

In the meantime, the vendor I was planning to buy the Marathon Plus from has sold out of all 700c sizes.

I have Rivendell Roly Poly tires on one of my bikes. 250 mile so far including about 50 off road without a single flat! Haha, I don't ride that bike much...

I'm think about getting the Rivendell Ruffy Tuffy which is the Roly Poly with thicker rubber and a kevlar belt.