**Updated Mar. 2008***
The list is intended to the to be a guide to the very best vst plugins. There are a lot of them out there of greatly varying quality. It makes it difficult to sort through so I just wanted to help. I included things based on personal experience, reputation, usefulness and overall quality. There is somewhat a slant toward simplicity & usefulness but I think that is justified. They are divided up by category to help you find what you may need. Some are listed multiple times where necessary. I added notes where I felt clarification was necessary.
There always is good stuff for those that dig. The bottom section is were all the weird and wonderful plugins are that deify classification.
I will keep up the list. I always have a eye open for good stuff. If you have any suggestion you can send them to me here.
Also be aware Computer Music magazine and other like it often come with a disk of good free plugins. CM has a whole suite of exclusive plugins.
Also if you don't have a host check out Reaper. A fully functional DAW software that host vst plugins.
The "*" means Mac compatible. Mac might be interested in this list of ports.
Synths & Instruments
Basic (Commodore 64/sid chip)
Greenoak Crystal* (deep and powerful)
Iblit (mono)
Shortcircuit (sampler)
KarmaFX Synth (modular)
Superwave P8 (va)
Synth1 (Nord Lead 2 clone use google translate feature to read page)
Odo Six & Double Six (fm's)
Chimera (unsual hybrid as name implies)
Sounds of Nature (a collection of synth that make sounds like bugs, rain, etc.)
Triangle I (mono)
Triangle II (mono)
Taurus (bass)
Tweakbench synths (small & many)
Ugo's String Theory 1.5, Rez 2.0, Texture 1.2, Motion 2.8 (cool and different)
Oxytocin (slighy twisted va)
U-NO-60* (Juno 60 clone)
Grainz (granular)
Abakos (subtractive)
The Element of Surprise (a single button that generates random patches)
Cygnus (pad) & Morphiza (electric oragn)
Dirtbag (Hammond)
Mr. Tramp (Wurlitzer) & Mr. Ray or Mr. Ray 73 (Rhodes')
Amplifier Simulation
Juicy77 (Gibson GA77 guitar ampish)
Simulanlog Marshall JCM900 & Fender Twin
FrettedSynth (6 differnet ones)
Studio Devil BVC (guitar amp)
Compression/Dynamics/Limiters
W1* (Limiter just like Waves L1 the first mega weapon of the loudness wars. Can get a nice skinned version from betabugs*.)
Blockfish & Floorfish* (compressor & expander/gate)
SSL LMC-1* (compressor)
TLS Pocket Limiter & Saturated Driver
Kjaerhus Classic Master Limiter
X-CITA (BBE maximizer like)
Delay/Echo
Echomania (vesitile & somewhat crazy)
maelcum (tape sim)
Bionic (good for ping pongs)
ELOTTRONIX XL (Fripptronics like delay)
De-esser
Distortion
TSS (tubescreamer)
Simulanlog DS-1, SD-1 & Tubescreamer
Drums
Rebirth (ok not a plugin but can rewire it in and have a 808 & 909)
Drumatic 3 & Drumatic VE (synths)
ERSDrums (drum machine like)
DrumTrig (drum sound replacer)
toad (NES drum synth)
snare (a modeled snare
EQ
Filters
Minion (fun interface)
Frohmage* (crazy filter)
Guitar Related
Midi
Modulation(Chorus, Flangers, Phase Shifters, etc.)
MonstaChorus* & SpinBug (rotary sim)
Reverb
Sir (convolution)
Sampler
shortcircuit (powerful sampler)
Stereo/Imaging
Tools
Span (spectal analyzer)
Fre(a)koscope* (spectal analyzer)
s(M)exoscope* (waveform visualisation)
Gtune (chromatic tuner)
GSnap (pitch correction)
GNorm (prevents denormal problems)
Sidekick (side chainer)
Multi-fx, Audio Manglers & the Weird and Wonderful
Glitch (everything step sequenced awesome!)
hypercyclic (a super gater/arp)
Free Amp 2 (guitar rig like)
bufferoverdrive* (makes your audio glitch)
Frohmage* (crazy filter)
truc (multifx for live performance)
Camelcrusher* (distrotion+filter)
breakdown (step sequenced filter)
cairo (tempo sync gate+distortion)
grublebum (synth effect)
mashup (crazy delay)
pudding (grain delay)
sideslip (sequenced pitch shift)
yionk (kind of a virtual chaos pad)
Cyclotron X2 V1.0 (pitch shifting from Mars)
Housebeast V1.0 (WTF)
GGrain (granular resynthesis)
Beta Bugs' Chorrosive, FlofiDeluxe 1.1, GetaBlitchJR*
Darkware (bunch or glitchy stuff)
LFX-1310* (hardware like multi-fx)