as far as Logic plugs go (that have not been mentioned yet):
- You should get to know the EVOC20 (all forms). This comes as a Synth/Vocoder, Filterbank, and Track Oscillator. You'll come up with some pretty crazy stuff!
-ESM, run through your distortion of choice--quick and easy acid lines and 303 basslines
-If you get 7.1, the EFM1 is a neat little tool for FM sounds--not really flexible, but quick and easy to use.
If you want to venture outside of Logic, I recommend looking at MOTU MachFive---next to Kontakt2, it accepts the most sample formats w/o separate conversion software. I havent heard much of anything good about Kontakt though...however I know someone who ditches their GigaSampler
for MachFive, and is more than happy.
best of luck!