In no particular order:

• VGMix - A site dedicated to remixing music from video games. You love it.
• Gary Numan - Punk, synth, industrial rock, he has done a lot of things, and it's all good.
• Kraftwerk - The founding fathers of all electronica and techno.
• Amplifier - Excellent progressive rock.
• Frank Klepacki - Industrial electronica from the Command&Conquer series. Jukebox applet at the bottom lets you listen to it all for free
• Trademark - Some good clean electronic music, plus decent industrial electronica, with a British accent. Unfortunately it degraded into mediocre dance music.
• Sefiros - Free industrial/ambient/electronic/whatever music .
• Torley Wong - Free techno[logical] music, and amazing at that.
• Divinorum - More Electronica.
• Mushy - Great free music in a huge jumble of hybrid genres.
• The Crystal Method - Even more electronica. Phat beatz.
• Linkin Park - Nu Metal, apparently. Ignore the screaming and it is pretty decent.
• Nobuo Uematsu - Author of the awesome music from the Final Fantasy series.
• Hate Dept. - Music to shoot people to.
• Pitchshifter - More music to shoot stuff to.
• The Prodigy - Yet more electronica.
• Badly Drawn Boy - Acoustic guitar and so forth.