The largest I fit in my 2002 Crosshairs is 38c, slick. There was a couple mm on each side, but I could not fit a 42c IRC knobbie tire. The limiting factor is in the chainstays, where the fender will clip, but won't really go in between like in the seat stays. You can fit 45c in the seatstays. Here are some pics of me totally voiding any chance of warranty and getting my crosshairs to fit 45c tires:
http://picasaweb.google.com/11111394309 ... sterCross#
Basically involves some bent MTB stays, and since I was going through all of that, I added a disc mount and chopped off the canti posts. The local bike shop powder coated it mirror black for $60. I'm still waiting on brakes, but I rode it around the block and it didn't break. One can easily see I'm not a professional frame builder.
Good all around is very dependent on what your definition of all around is. WTB allaroundasurous or something like that is ok for mostly road, dirt road, though it'll let you slide when you corner hard in grass.