Most laptop speakers are compromised by two things. Physical size and with most machines, the cheapest components. If you are up against those two, then any improvement is going to be miniscule, I think.
External is the way to go if at home. either connect to your home stereo, or through a wireless router, for superb quality with minimum fiddle factor. For mobile use, I would suggest a bluetooth stereo headset, (if the laptop supports same - if not, a mobile bluetooth dongle does the job) which also works a treat.
Conan