I'm doing a trail bike build on a Trek 700 frameset. While I'm not interested in competitive cyclocross, I want the bike to have cyclocross type capabilities as far as being able to to from paved surfaces to gravel and dirt roads, turf and even some loose trail. I've decided on the Schwalbe Smart Sam tires but want some input on what size would give me the best all around performance. The fork won't take anything over the 40mm so the 45mm is not an option. I've asked around the LBS and a few area cyclocrossers and have had answers ranging from "bigger is better" to "anything over 28 with some tread is fine".