For a taxi, in case you dont find a collective taxi or a bus, take a regular taxi. not only this, take the one of my new Palestinian friend, Sam... a cool rock musician who drives cabs during the day... and speaks a very funny English (read: not so faint Louisiana accent - and the victim of many of my jokes). He knows everything and everyone, and he's witty as hell.
Taxis are the best way to get around the city, but be prepared to pay for them. Make sure the driver turns on his meter and you see his taxi identification someplace. As a woman travelling alone, the cabs were great! However, one insisted I go have chai with him in the social centre of town. This is NEVER a good idea. Though culture is changing rapidly there, a woman and man in public is a sign of their engagement to one another. I did not go, and claimed to be married already. ALWAYS have an escort, preferably male.
Another cab became so lost trying to find my hotel from my horrible directions that he asked 3 of the major hotel doormen in Shemesseni(?) district where it was before finding the place. He spoke little English and I spoke little Arabic. The meter read 4JD before I arrived at my hotel, which should have read 2JD, max. He gave me the ride free of charge.
Women should try not to sit in the front with the driver, generally. There are exceptions, but some drivers take this as an invitation to make advances.
Meter fares are not arguable generally, do not sport with the driver's intellegence and try to haggle.
From the airport the official price should be betwen 20 and 25 JD. Around the city always ask to turn on the meter as, the few times I did not ask, prices could be 8 times the meter one.