i'm hooked on pandora.com
I like all kinds of music. From The Fray, to Toby Keith, to Armin van Buuren. So really, from modern rock to country to techno. I like it all. I have a ton of songs on my iPod, in all of those genres. I have playlists for when I run and when I am just hanging out with family and friends, and even some for road trips to New Ulm, where my parents live, or to North Dakota to my in-laws' farm.
What I can never do is find music that is like the few bands that I like. A few weeks ago, my brother messaged me and said to check out a site, Pandora.com. Pandora is part of The Music Genome Project. What they have done is come up with a system that recognizes like songs, not quite by genre, but more by what the music is like by instruments, by the lyrics, arrangement, etc.
So, I typed in "The Fray" and sure enough. I get songs by them, by the Goo Goo Dolls, Oasis, Green Day, etc. Pandora creates a playlist of like songs. All the songs are alike, and song that I have heard (mostly) but never remembered or thought to download.
I listen to it every day. You have to sign up if you want to create a playlist. You can create multiple playlists as well. I have one for all the kinds of music I like. It has a nice interface and is easy to use. My wife and my mom have signed up as well. Go ahead and give it a try. You'll like it and find songs that you like as well, and its free!

The biggest mistake I have made was to head to lunch several times and forget to pause it. I think then it just has all sorts of songs playing without you teaching it what to give you :)
It lets you run the Pandora player as a stand alone app, and gives you global hotkeys to run it
I have done the same thing with walking away from my computer and letting it just play and play. I have been getting better at it though. I have seen a HUGE improvement in my "station" when I stay on top of it.
@Jason
I just downloaded OpenPandora. It rocks! Thanks for the info!