Cool thread. Do I need to post in a particular format, or is just listing a few music acts ok? Here are some that I like.
Splashdown
This band is really good, but really hard to describe. Wikipedia says they are a "combination of electronica, rock, jazz, and Middle-Eastern influences." Since the band broke up, they actually encourage people to find their songs online and download them for free. I'd highly recommend the album "Stars and Garters".
Our very own Shael Riley
This is one of my favorite albums. No, I'm not joking. When I downloaded his album Toybox (which is also available online for free), I was expecting 12 tracks of Music of My Groin (not that it would have been bad thing). Instead I was very surprised to hear a very unique blend of chiptune and pop music which he calls "Bit Pop", and some of the catchiest melodies I've heard in a while. And of course all of this is done with Shael's special sense of humor.
Machinae Supremacy
This Swedish band, self-defined as "SID Metal", combines awesome riffs and solos with a lot of Commodore 64 SID chippage to back it up. Their vocals are very catchy and melodic. A lot of people I've talked to say the singer's voice grates on their nerves. They have several instrumental songs if this my be the case for you. Personally, I like the vocals, and if you take the time to get used to them, you'll wind up enjoying his unique style. They have 2 albums available for purchase (both of which I would recommend), but they have over 30 songs on their website for free download, in mp3 and ogg format. I'd recommend trying out some of the stuff toward the middle of the list and then check out the other stuff if you like it.