Voxengo GlissEQ
I use Voxengo products every day and am still blown away by the quality of the EQ/filtering effects. GlissEQ and Redunoise are simply unique and can work wonders with poor source material.
The most recent purchase has been the Analogflux Suite. This really can impart a beautiful feel to a track. TapeBus is the best tape emulation I've heard yet.
You could pay thousands to get a plugin pack which isn't as good as Aleksey's plugs - they've certainly helped my studio out financially!
If you're not sure about buying a Voxengo product then download the demo and spend some time using it on your own mixes. I can't imagine how anyone could fail to be impressed.
Your products are amazing!
From your incredibly useful free-plugs to the very cheap and fantastic sounding payplugs.
I am recommending your company to anyone who'll listen, so please keep up the good work!
All the best,