I bought an iMT520 on woot awhile back (for $50) and it's been awesome. Sound was surprisingly good, battery lasted just about as long as advertised, and it's small enough that it fits in my laptop bag so I can take it around with me.
"From your favorite FM stations to your favorite MP3s this may be the ultimate portable sound machine. Leading technology delivers the total experience of sound at every step of the adventure. The rechargeable battery lets you unplug your music so you can share your playlist in any scene. The versatile handle lets you effortlessly take your sound wherever the party goes doubling up as a stand so you can kick back. Switch on and tune in with FM radio and 4 station presets delivering crystal-clear reception. Outdoors indoors with friends alone; with the inMotion Classic the world sounds better."