Kenda Bluegroove Stick-E 2.5 in the front on my 5 spot. Its not the fastest but, it sticks like glue to rocks and dirt so that makes up for it. Moutntain High Cyclery has the best prices on these as well.
Some deals on Nokian tires. Check their auctions for best deals.
I hadn't heard about IcyclesUSA before last week. Bought a tire from them that was about 1/3 of what my LBS wanted ($9.something vs $30something.) Arrived in about a week. I can't complain! I've gotta imagine their auctions have pretty good deals if you know what you're looking at!