Azo if you can find it, or Lodima, which is also a great paper. I also use a K&M point light source which yields very sharp prints. There's one for sale on eBay right now, but it looks pretty used. I'd buy it but I already own 4. Here's the link so you can see it. Point light sources make the best contact prints IMHO.

http://www.ebay.com/itm/Kodak-K-M-Po...item20d9f68094