After a long day of pretending to pay attention in lecture, one of the best ways to unwind is some really good music. Sure, you could listen to the same old tunes you’ve had in your iPod since freshman year or even turn on the radio and listen to obnoxious DJs and commercials—or you could try something new. In the world of online radio, there are two rapidly expanding websites providing thousands with high quality streaming radio stations custom tailored to each user’s musical tastes.

First up is Pandora, a service that runs inside your web browser at http://www.pandora.com/. The user inputs a band or song, and then Pandora generates an online radio station just for you based on what you put in. You can add more songs or artists to that station and then rate the songs it spits out with a “thumbs up” or a “thumbs down,” which helps Pandora tweak the station to exactly what you like. It allows you to make several stations from scratch or listen to other stations that users have shared.

Pandora also has some advanced features that allow you to share your stations with friends, the coolest of which is the “favorite songs list.” You have the option to add songs to this list, which are put on a website that you can adorn your instant messenger or Facebook profile with. Next to each song on the list is a link to the station you were listening to, a play button that allows anyone to listen to a sample of each song, and links to the iTunes music store or the album on Amazon.

The reason why Pandora is so great at really honing in on what you want to hear is that every single track is analyzed, as per its Music Genome Project. The station tracks down songs that share “musical traits” with the songs you’ve rated favorably. After several songs, Pandora will have a better feel for what you want in your custom built station.

Last.fm (http://www.last.fm/) works in a completely different manner than Pandora. Last.fm keeps track of the music you listen to in Winamp or iTunes with an Audioscrobbler plugin. After using it for a few days, you’ll have enough music for Last.fm to assign you “neighbors” based on your musical tastes. The free version will allow you to listen to music based on what your “neighbors” like, but not on your own personal music library. Last.fm also keeps a list of everything you listen to and arranges your most played bands, albums, and tracks on charts that it displays on your public homepage.

The best part about Last.fm is the Global Tag Radio feature. A paying member will be listening to a Death Cab For Cutie song, for instance, and tag it “Indie Pop.” That song then goes into the “Indie Pop” Global Tag Radio playlist. This system has its ups and downs, though, because while some people are excellent at tagging their music, others seem to incorrectly tag songs out of pure hatred toward those who like a genre. For instance, I was listening to the “Metal” station, and Barry Manilow came up between Black Sabbath and Pantera. Some stations were well-tagged and had a very diverse selection of music, but others were just so poorly tagged that they required near-constant attention.

Both sites require you to sign up using an e-mail address, and they have free versions for use. On the whole, I like Pandora better than Last.fm—it generates better music stations, and it has been a much better helper with music discovery. I can pull up my radio stations on a friend’s computer without having to install anything, and I can share clips of my favorite songs quickly and easily using Pandora’s Favorite Songs List. Last.fm’s stand-alone player runs somewhat faster than Pandora in Firefox, but because Pandora requires no install, the portability factor far exceeds the slight gain in speed.

I still do use a few of Last.fm’s Global Tag Radio stations, and the voyeuristic charts of my music listening are pretty cool to look at. I don’t like the buggy-ness of the Winamp and iTunes plugins required for Last.fm, the poor accuracy of music suggestions, and the lack of functionality of Last.fm’s song rating system. In my opinion, Pandora wins this battle and is therefore my suggestion for free and customizable online radio.