As the title says. I am currently running knobblies, but am finding myself doing a lot of riding on the road. Knowing nothing about slicks or semi-slicks I thought I would ask those that do.
+1 for Schwalbe Marathons. In the dry they're not as sticky as the WTBs that came on my bike, but they're harder wearing and don't get punctures. The performance in the wet is about the same as far as I can tell. In the snow and on grass the rear wheel slips more easily.
I went for Continental City Ride - I'm not a serious cyclist - just wanted better rolling tyres on one of my mtn bikes for riding out of the door to help general fitness, so didn't want to spend on owt fancy. These were a pair for £23 including delivery from Edinburgh Bicycle Co-op on line. Got 'em inside 2 days and they seem fine - just right for my purposes anyway.