i find these sorts of questions/threads a bit difficult: "i have a noise, any ideas?". seriously, how are we to know without seeing/hearing it ourselves?!
also, how does a driveshaft bend? what sort of condition is your car in, and what accidents have occurred?
anyway, as above, it could be any number of things, so hopefully you can sort it out:
*tyres/wheels: tyres worn down to wear-indicators; bulging tyre; low pressure; buckled wheel
*hub/bearings: worn wheel bearing
*suspension arms: worn bushes; damaged/ bent arms (if the drive shaft is bent, perhaps the car has hit a gutter/curb at high speed)
*dampers/springs: worn damper/shock absorber
have you had an opinion from your mechanic or alfa dealer? how long has it been occurring for? any incident that may have started it? the more info you can provide, the better. let's try and narrow it down. but ultimately, you may need someone to actually look at the car and drive it; may not be able to help over the forums.
that's my AUS$0.05.