Yeah.. like Pavan, probably 80 or 90% of the music on my Zen is techno/trance/speedcore.
Typical mainstream trance suggestions are Paul van Dyk (Nothing But You is my favorite, but most of his others are good too) and Tiesto (I like Traffic or He's a Pirate). Check out Pendulum if you want a bit of a more faster, pounding type thing. Check out the Bonkers CDs if you want a more bouncy hardcore-type feel (songs like Go Berzerk or Enraptured Soulz). One of my favorite songs right now is
Rave Phenomenon. Finally, take a look at VA's long mixes (like "VA Hardcore Trance" or something like that), they usually have some good stuff in them.
Hit me up on PM or AIM if you'd like some more specific suggestions or whatnot.