The Yamaha PDX-11 Portable Speaker System ($100) is less than 10 inches in diameter, but it pumps out crisp audio with amazing clarity. It's all thanks to the two-way speaker system, a large 4-inch woofer and a dedicated tweeter delivering remarkable mids, highs and lows. The PDX-11 features a rugged design, an iPod and iPhone dock, a sturdy metal handle and a tough enclosure available in four colors.