Sorry to have come to the "party" so late.

If you're still interested, I might recommend the following freeware synths:

Pads - Superwave P-8 and Galactix

Nord lead sounds - Ichiro Todas Synth 1 - Actually an all around excellent analog modled synth also excels for simple yet detailed editing.

FM Sounds- Ugo's Texture and Syncer's Polyvox station. I like Texture as much as I do Image Line's Sytrus, which cost me 179 USd. Apparently so do many of KVR's users, as it's tied for the top rated free synth with RGC's Triangle II.

Mono analog modeled- RGC's Triangle II. Great leads and bass sounds.

Hybrid FM / Wave based ( soundfonts ) - Crystal. This one is usually near the top of KVR favorite's list.

Agressive in your face sounds - Almost any of the "Killer" softsynth series, Dash Siganture "DaHornet", and "Karnage".

General all around analog modelers- Lin Plug's "Alpha" and Andreas Ersson's "Polyiblit".

Tonewheel Organs Rumplerausch's "ZR3"

Honorable mention - Mik Sybrandt's series of MIK softsynths and Krakli software's series of softsynths.

There is enough to play around with there for quite some time. Most of these can be found over at the Kvr_Audio site.

AJ