What is the best vst synths (free or commercial) in your opinion… I know some might find this question to be stupid, but anyway… 
- Reaktor is a monster, but not necessary in all cases. You can almost make anything you can imagine, but it takes some time to get into and the risk of ending up constantly improving your synth takes away time from the actual musicmaking… a bit pricey, but you get a lot for your money.
- Vanguard has a kind of “uniqueness” to it and can make most analog bread and butter sounds nicely.
- Z3ta+ is real good but a bit heavy on the CPU
Don’t forget the incredible Korg Legacy collection…
most of all i like atmosphere, triangle (free even), vanguard, realguitar and so on… ; )
Linplug Albino 2.1 and NI FM7/Pro53 are very very good (and stable)
agree,
FM7
Pro52/53
Realguitar
Reaktor
my favourites are
Slayer v1.5 and v2.0 (reFX)
Kontakt (Native Instruments)
Pentagon (z3ta+ makers)
edit
anyone knows a good AM synth ?
For tb303 lovers look 4 “the bass line” from audiorealism…
The best emulation you can find…
and pentagon I Great sound !
Motion - by UGO, is a nice synthedit plugin that makes some awesome soundscapes and textures. Pretty good for a free plugin.
Morpheus - this is an awesome wave-morphing plugin for creating gritty textures and soundscapes. It’s not really a synth, as it uses 2 wave files (of your choosing). One is the sample, the other acts as a modulator. There’s some great presets available for download and it’s worth getting them in the larger of the 2 downloads. Massive CPU hit though. 
Z3ta+
it always 
me!