Stuart: You have some quite demanding lenses, so you will need a decent support.
In my experience a ball head works well for macro photography. But you will need a reasonably large one, and I would guess at least a 30mm ball. I used a Slik 800 Pro ball head for years, and its decent enough, if a bit rough. I don't really like the quick release and I suspect you can find better for the same kind of money. FLM make some nice ball heads that get decent user feed back. See
www.SpeedGraphic.com for details. There are also Chinese Benro ball heads that offer remarkable value for money but they seem to get mixed user feedback. You can get them from numerous places including Microglobe and ebay.
Regarding a tripod, I use a Uniloc 1600 and have done so for 8 years. It is a remarkable, well made and versatile tripod. However, this morning the locking handle sheared the threads on the bent bolt, so it is unuseable until I get replacement parts from Uniloc. I used to have a Benbo Trekker, and that failed for the same reason after 18 months. I still recommend the Uniloc 1600 as there is nothing like it and it only weighs 2.4Kg. It is also cheap compared to the alternatives. IMO the Benbo Trekker is too light and mine was not well made (a leg fell off after 1 year, and the handle sheared off 6 months later).
Even with a good support I suspect that you might have problems with vibration with the D70 as it does not have a mirror lock up.
Leif