I am looking at a new 700c touring bike and I would without question or second thought go with Continental Gatorskins (or Gator Hardshells) I use them on my commuting bike and they are great. The one time I got a flat was about 200 feet from my house due to a pinch flat because I had an early morning appointment and didn't have the time or energy to pump my tires and thought it would be fine and then boom I am almost home and I hit Lé hole du pot. I have a lot of miles on those tires and aside from a little dirt they look fairly new and roll great even though they have been through some pretty rough and nasty streets. I would probably go with 28s or 32s rather than the 23s I normally run for commuting.

I have Conti's on all of my bikes and the only reason I might go with something else is if I was doing tubular tires and had the cash money to go with a A. Dugast handmade tire. The tires on my current touring bike are just fine Comfort Contacts and my vintage machine has Grand Prix Classics. However I haven't heard a lot of bad stuff about Schwalbe and they are also German so you probably won't go wrong with either but I like my Conti's just a wee bit more.

That all being said depending on your rims certain tires might be wider or narrower than advertised (or sometimes because of some number fudging by tire companies). Also don't waste time with disposables go with a nice pump and build up a little arm strength. CO2 is fine for racing when speed is important and you don't need air in your tires for much longer but for the long haul a pump and normal air works better and escapes less quickly. You can carry some CO2 as a super emergency thing but I would still rather have the pump.