You may have heard about Google Play, a recently-released online store for music, movies, books, and games. You can buy lots of cool stuff through Play, but for this tip we'll focus on something you can do for free: access your music anywhere. Similar to the iCloud service on iOS platforms, Google Play lets you upload your music (up to 20,000 songs) to the cloud to be enjoyed wherever, for free. So you don't need to worry about syncing your phone with your laptop every time you buy or rip a new album. Just be careful about network streaming if you're on a metered data plan (to avoid overage charges, you can always set Google Play to stream only over Wi-Fi).
If you don't want to get too tied up in the Google ecosystem, there's another elegant way to accomplish pretty much the same thing: DoubleTwist Airsync. The program has two parts: the first is an iTunes-like desktop client that functions as a multimedia player. The second is a mobile client application that lets you stream to and from the computer. So if you download an album on your computer, it'll automatically sync to your phone, and vice versa.