Features come and go in the rapidly evolving MP3 player space. One that has enjoyed fluctuating popularity is the built-in USB interface, which allows a device to connect directly to a computer without a cable. This "plug-and-play" capability is currently out of fashion, but Sony is trying to keep the dream alive with the B-Series Walkman. The entry-level offering is aimed at active users and is priced competitively at $44.99 for the 1GB model and $59.99 for the 2GB. Battery life isn't as impressive as other Sony Walkmans and the screen is tiny, but the B-Series hits the mark with an array of features suitable for on-the-go use.