On a paved road, any slick is going to be way better than any knobby off-road tyre 🙂
I like the IRC Metro 26" slicks for MTBs.. very nice, completely slick, and available in narrow, light weights too. There's a kevlar belted version available as well.
IRC Metro Info: http://img.epinions.com/images/opti/3b/8c/bikeTiresAllMetro.jpg
I have also used Michelin Wildgripper City tyres; these are nice -- BUT, as it has a treaded pattern, small stones can sometimes stick in the treads, and also in these little holes that are in the middle of the tread for no apparent reason. If you are thinking of sometimes riding non-paved, somewhat gravelly (but not off-road) trails I would err away from these; if this doesn't concern you, they are a good tyre.
Wildgripper City Info: http://cycleus.webmichelin.com/tires/city1.htm
Wildgripper City Reviews: http://www.mtbr.com/reviews/Tire/product_79577.shtml
My sister uses Tioga City Slicker tyres on her MTB for basic inner city commuting and likes them; though from some review reports, it sounds as though the sidewall strength isn't quite up to par
Tioga City Slicker Reviews: http://www.mtbreview.com/reviews/oldertires/product_23337.shtml
It might be worth a mention that tread patterns on slick road-going bicycle tyres have no effect at all with regard to aquaplaning and wet weather performance, like on a car tyre -- any tread patten is there for looks more than anything else.