There are many photographers and third party developers creating and sharing interesting and complex presets. Lightroom Exchange is an excellent location for finding third party plugins for Lightroom (many are free downloads some have a small cost, and some may only be for Mac, while others are Windows only). Click the link above go to Lightroom Exchange, or, in Lightroom, select File > Plug-in Manager, then click on Plug-in Exchange (lower left) to automatically be taken to the Lightroom Exchange site On the right, you can choose to search on all catigories of Lightroom plug-ins or simply the Develop Presets.
Jeff Tranberry from Adobe blogged about presets that he has found and posted to the Lighroom Journal – an excellent resource!
Jack Davis has created over 190 free presets for Lightroom with onOne Software and several photographers also have presets for sale including (but certainly not limited to) Marcus Bell and Kevin Kubota.
Please feel free to share your resources for others!