Afew of my picks. I have to confess tat I have not heard the remainder of the SMP catalogue but im sure theres a few more classics out there.

Shorty Bone - Dreamphase
Sunbeam - Outside World EP
D-Lay - The Dreamer
Aqualite - Outback
Semisphere - First trip to Semisphere
Urban Tranceplant - Enjoy EP (Ready to Flow)
Retroflex - Feel the World EP
Sound Source - Voice Control
Cenobyte - tales from the A-side
Suck-Cess (Suck #50)
Final Fantasy - Controlling Transmission
Pro Active - Back to Atlantis