I use a Manfrotto 029/Bogen 3047 3-way head, as it is quite cheap and uses inexpensive and readily available QR plates. This will hold up to 7.5Kg and weighs in at just over 1Kg. The QR mechanism has a lock and is inherently self adjusting. It may not be elegant, but it works.

If you are tempted by a ball head, make sure it has friction control.