I may have overlooked, but I didn't see links to these 2 usefull sites:
analog x has some usefull tools I think
I use the 'autotune' to tune my one shot samples to put in my software sampler. 'Say it' is a nice sounding text to speach program, usefull for making robot sounding vocal samples. The 'vocoder' is a very simple one but has a nice sound.
I also use buzz machines It's a virtual studio, not the most stable software and not the most handy thing for sequencing, but has a lot of nice tools and a good sound. To give you an example, I made this song with Buzz: B913 is a hoax