Depends what you look for in a texture, really. The best free one out there is Eowyn's Shari. She's gorgeous! I love Ebony and Ivory by Dalinise and Stormi - great, hi-res textures that don't look like photographs but are still realistic. If it's photorealism you want, Dalinise's Brown Sugar is beautiful. Dalinise's Imana is also gorgeous, but I've found that one difficult to light in Poser because she's very dark.