Treo 650 with cheapo standard 3.5mm earbuds with 2.5mm converter for use with the Treo (but this way I can use them with standard plug devices as well) - serves as PDA, phone if I travel domestically, mp3 player, and Audiofy book chip player for language lessons
Boxwave multi-plug (cigarette lighter/standard north-American 2-prong) with mini-sync adapter for the Treo and Empower adapter
Sony DSC-P5 digital camera (I know, it's old and clunky but I'm waiting for the 1 device solution to replace it and the Treo) with extra memory sticks, spare battery and small travel charger
Dell Latitude D610 with AC adapter
512MB flash drive
Most of the time everything else I pack since I travel carry-on only.