I realized that I was getting a lot of flats in my front tire, and it is usually the back. The other day when I was taking my upgraded bike (lots of XT/Deore parts) out for its first spin I got a flat on the first lap of the my regular training ground in Prospect Park. So when I went to put the spare tube in I checked the tire thoroughly and I could see a lot of embedded shards of glass so it was only a matter of time before I'd get yet another. This tire is a WTB Slickosaurus, and I also realized I've had it mounted on various wheels for 3-4 years already. OK, so it had to go.
So I went to REI where I have a $100 gift card and checked out their tire selection and saw they had Gatorskins in 26x1 1/8. These are actually a decimal sized 559 tire for MTB but they use the non-standard sizing and I don't know why. I put it on my bike, but it is 25 degrees outside and I'm not going out there.
Anyway, my question is, has anybody used these for commuting? They seem narrow and totally unsuitable but I bought it anyway. I use GP4000s on my road bikes, and I even have a supply of those from when they went on sale at PBK. I used Gators when I did my climb of Mt. Haleakala a few months ago (I made it up 6000' over 20 miles of nonstop climbing). They seemed like a decent choice for that, and that's what the rental bike had. But climbing a smooth road up Haleakala is not the same as riding the streets of NYC with a bag on a rack.
Ever situation is different and everyone has their preferences, but I would think 1 1/8" would be wide enough for commuting on city streets. Seems much wider then most 700c tires I see people commuting on out here. Maybe your roads are much worse or you just prefer a much wider tire. I wouldn't think a bag on a rack would have a huge impact - I assume you don't have a 50 lb bag on there. I guess it would add some weight over the rear tire so make sure you have enough air in rear tire.
I can say I have been very happy with Gatorskin tires as far a flat resistance goes. I have over 1000 miles commuting on my 23mm gator skins, including some rough roads, with no issues so far (knock on wood).
Good luck when you test them out, and look forward to hearing how the work out.