I know if ain't broke don't fix it - but I'm itching to try some new tires on this my first road bike/commuter/light touring setup.

I'm about 230 and have been riding for a while now with Velocity A23 36h rims and Marathon + 28c. One of my main concerns starting out was to have some bomb-proof wheels and tires - and now that I've seen that this setup holds up I'd like to see I can get away with less rolling resistance. I've had the bike since September and am only now noticing a slight wobble in my rear wheel - so they've held up pretty well. I ride 15 each way - 5 pothole city / 10 lakefront path. I also ride a lot in wet weather - so I realize that from the sound of all this I should just stick with what I've got - but like I said - like to try something different just for kicks.

I'd like to try something that's a little less slow -- Gatorskins? GP4000s? Can I get away with going 25c?