I'm a big fan of Phutureprimitive. His 2004 album came out on Waveform Records, which has been one of my favorite labels for a good 16-17 years now. He actually just came out with a new album quite recently.
I also like Tripswitch. I have the 2CD version of his 2005 album, which has a bunch of remixes. The best is Gaudi's remix of Exiled, which I featured at my 30th birthday set (but I digress...) He came out with a new album last year. It's pretty sedate ambient. I've listened to it a few times, but I've yet to "crack" it, if you know what I mean. There's a brand new album for 2011, which I have not heard yet. I have entirely too much music to listen to, and there are some things I just have to sleep on.
The two artists that have been occupying my time recently are Pretty Lights and Heyoka. Unusually, at least for me, both of these guys are really big with the younger generation of club goers. Pretty Lights is not remotely ambient or IDM. Early in his career, he made mashups from 60s and 70s soul records. Recently, he's been producing uptempo breakbeat tracks with some dubstep-influenced basslines. This is probably his most famous work:
The vocals are sampled from Etta James' Something's Got a Hold on Me and the distinctive guitar riff is lifted from Judy Clay and William Bell's Private Number. Pretty Lights is not the first artist to sample either of these tracks. Nightmares on Wax sampled Private Number mere months before in his track "You Wish." Paul Frankland sampled the Etta James track way back in 1994 on the track "Mama 6 Pt. 2" from the Journeyman album. Paul is more famously known as the ambient artist Woob, but that's a topic for another day...
Unfortunately, so is Heyoka. I've gotta finish some work today, and his dubstep-IDM-glitch-dnb madness will have to wait.