I have a couple travel systems, as I travel a bit. I think the absolute best travel system I've had is the Cambridge SoundWorks Model 12. 3-way amp, with 2 satellite speakers, and the case is a subwoofer. Brilliant. I often use different satellites to mix it up if I'm traveling by car....Gallos and Mirage V2s. So far the Mirage had the best integration with the amp and sub. I also pack in it a Jolida GlassFx DAC, Audioquest KingCobra cables, and hand braided speaker cables. :-D
Most other systems lack bass, and that just isn't satisfying for me. This sends everything under 120hz to the bass case. All for under $500 (for the main system), and all in a tough-as-nails bass case. I've been taking mine all around the country for 9 years with zero problems.