drumsynth -
http://www.mda-vst.com/ its supposed to be mainly for drum
sounds, but you make all kinds of stuff. freeware
orangator - i find it difficult to work with, but you may not. good at
making string/pad sounds. freeware
simsynth - pretty cool, get more dance oriented sounds out of it i think. i
dont use it anymore, but you may like it. shareware
:jason (i've got a fresh opinion now)