Link: http://www.matthewgood.org/catalogue.php
If you're at all unfamiliar with Matthew Good's catalog, you now have no excuse.
For whatever reason, Matt decided to upload 256kbps "streaming" MP3s to his website for people to check out. Now, admittedly, many of his most popular songs aren't there. But several of my favorite songs of his are. And they're fucking brilliant.
In particular, be sure to check out the songs from Avalanche, Audio of Being, and Underdogs. (Not that you should skip Beautiful Midnight, but most of my favorites from that album aren't there, save "The Future Is X-Rated" and "Giant". And, at the moment, the White Light links are broken.)
I'm not even sure I can pick favorites from the songs he's made available, as most of them are absolutely amazing. But if I have to, start with these (in some random order):
"While We Were Hunting Rabbits"
"The Future Is X-Rated"
"Everything Is Automatic"
"Avalanche"
"Truffle Pigs"
"The Workers Sing a Song of Mass Production"
"Inescapable Us"
"Tripoli"
"Giant"
Plus "Empty Road" and "Alert Status Red" when the links are fixed.
Don't give up if you don't like the first couple. There's a lot of variety in terms of style and performance (some uptempo rock screamers, some mellow introspective tunes) between those songs.
And, if you know the trick with M3U files (*cough*notepad*cough*)...
DON'T DELAY!!!! GO NOW!!!!! I'M NOT KIDDING!!!!! NOW!!!!!!!!