have you got the ' high quality view port render' turned on? if so turn it off from the view port menu (shading/high quality render)(mine does the same thing with maya 8)
wacom, most people use one.., for PS or scuplting, Z Brush, ect. not important though (thats debatable, depends how much experiance you have or if you know WHY you want one)
to sculpt you need to 'select' the area you want to scuplt.
select the brush, make sure it is on 'push' or 'pull' whatever, not on 'erase.'you will need a lot of resoution (lots of lines on your geometry) for example a poly plane has default ten divisions, but knock that up to 50 or it might look like nothng is happening.
if you are using nurbs you must make it 'paintable' (make paintable, check help files) i haven't used the poly scuplt tool much except to import textures onto planes. i use nurbs for sculpting, i think that is the usual procdure.
take it easy and life will be easy