Agree with Adrian. The BTwin wheels are great for the money, even if the hubs aint sealed all that great! I have a set as back up that I turn to now and again.
How tight is the budget? If threadlock doesnt do the trick then expect to spend about £100 for a cheap shimano set, or £170 for a Mavic/Fulcrum/Easton replacement... Easton's EA70, Mavic Aksium, Fulcrum Racing 7.
EDIT - thats presuming you want racing style of wheel. If you're lugging weight I'd recommend a wheel with a MINIMUM of 32 spokes, preferably 36. For that you might need to investigate touring specific wheels