Most of my favourites are already mentioned, but this is a long thread, so I don't remember which ones. I will only list the ones I love the most. All of these can be found easy, just put the name and "vst" or "vsti" in google.
And guys, don't forget to try Soundfonts. "Sfz vst" will play them, and the unpackers and fonts are easily downloadable at
http://www.soundfonts.it/
There are some mean VST's and VSTi's available also.
VST:
Electri-Q Posihfopit, incredibly versatile and good sounding EQ.
IQ4, mind-blowing "dynamic eq",
http://www.platinumears.com/IQ4gui.zip
Digitalphishphones Dominion, attack booster / dynamic processor.
MyMag, tape saturation.
CamelCrusher, 2 overdrives, lp-filter + compressor. All of them sound extraordinary.
Tls Saturated Driver, a great master driver/compressor/limiter.
Tls Pocket Limiter, the best master limiter. L2 sucks compared to this! ;o)
Voxengo Boogex, guitar amp sim that works with impulses.
Gsnap, free autotune.
Voxengo SPAN, spectrum analyzer.
Effectizer, all fx needed for keyboards like the Rhodes and organ.
VSTi:
Prova, East-European grand piano. Makes me cry.
MrRay, the best Rhodes ever.
Aube, beautiful soft e-piano.
Plugsound Free, a great jazz drumset, some keyboards, a guitar...
Organized Trio, hammond.
Siecles, very frankencrazyish church organ.
And everything (free) from these sites:
http://www.gvst.co.uk/
http://www.kjaerhusaudio.com/classic-series.php
http://www.digitalfishphones.com/mai...em=2&subItem=1
http://www.voxengo.com/group/freevst/