Astral Projection - my first real introduction to goa and really, EDM in general. I was like 15 and living in Louisiana downloading Astral Projection MP3s over the 56k dialup connection. People can fly! Wheee!
Shpongle - Words cannot express the wonderful worlds that Simon Posford and Raja Ram have exposed me to with their various projects but Shpongle and Hallucinogen are by far the most influential to me. Tales of the Inexpressible takes me on a magical journey every time I listen to it with or without drugs involved and Divine Moments of Truth has to be one of the most epic electronic songs that I've ever heard and is nothing short of a masterpiece in psychedelic achievement.
Sasha & Digweed - No matter how much my musical tastes evolve, I never have a problem with any of the Exposure series albums being played at any time. Sasha & Digweed have this combined magic that is just hard to top by any standards. Out of the duo, Sasha is definitely my favorite. Airdrawndagger is yet another great work of art.
Some other candidates: Carbon Based Lifeforms, Autechre, Tiesto, and Armin van Buuren.