So I should soon be taking delivery of my new commuter!! Wheee.

It's pretty much a flat bar roadie that comes with 700x28 tyres. One of the first things I'll be doing is swapping out the tyres to something more flat resistant. Probably a set of Gatorskins at this point.

So first off, I don't have the specific details of the rims, but considering they come with 700x28 tyres, what is the likely range of tyre width I could fit on?

Secondly, what width tyre should I go with as a replacement?

Currently I have a roadie with 700x23 tyres so I'm used to riding with those. I wouldn't mind a slightly wider tyre for the bumps etc during commuting but I don't want to sacrifice too much speed. So can anyone comment on tyre width in general?

Or any other tyre recommendations?