Amorphous Androgynous is the most chilled stuff I find. Kai Tracid are a good trance outfit. Pendulum, I have a good set of theirs. Lemon Jelly are chilled. Orbital and Two Lone Swordsmen too, pretty nice stuff. Saint Etienne are quite chilled. Dance? The Prodigy are the best in that genre. Fatboy Slim rocks too, his first album is awesome. Moby are hella chilled, Play or 18 are the best albums for that. Much Against Everyone's Advice by Soulwax is cool. 2 Many DJs play some good electronica from time to time. Recommending music is hard, I have so much stuff and it's hard to classify some of it. Hmm, mustn't forget Björk either. Aphex Twin have some good trance remixes. The Crystal Method are pretty trance-esque; they chown too. Jedi Mind Tricks are probably more rap, but sort of trancey. Armin Van Buuren is a good trance DJ. Faithless, grab their greatest hits - they have some good tunes. Chemical Brothers, Beastie Boys... Ferry Corsten's Live @ Trance Energy 2005 rocked. Lionel Vinyl has some awesome remixed stuff. Markus Schulz is another good chilled trance DJ.
Finally, this is a mix made by a guy I know on IRC, he DJed for an online radio a couple of years back and he made it himself and let me have it so it's not warez (mods/admins ¬¬):
http://lidelse.info/MayMix1.mp3
Note: it's about 86meg so it's not for anyone on 56k, unless you have hella patience. But it's hella chilled and well made, you should like it.