It isn't cheap, but the Bose SoundLink Mini is an excellent-sounding Bluetooth speaker that is especially useful for those who travel frequently.
Bose SoundLink Mini II review: A great Bluetooth speaker gets even better - CNET
Bose SoundLink Mini Review — Gadgetmac
Vault LS Waterproof Case for Bose Soundlink Mini Review
Bose SoundLink Mini Review Box – G Style Magazine – G Style Magazine
Bose SoundLink Mini Bluetooth Speaker Review
TechTalk: Bose Soundlink Mini II 2 Special Edition Demonstration & Review
Bose SoundLink Mini II review
Bose SoundLink Mini Review — Gadgetmac
Bose SoundLink Mini II Review
Bose SoundLink Mini Review — Gadgetmac
Bose SoundLink Mini review
Bose SoundLink Mini II review: A great Bluetooth speaker gets even better - CNET