I use a Giottos Aluminium one with a manfrotto pano head. Ideally you need a centre column which can be adjusted through a number of angles, plus a hook for a counterweight.
The Pano head has two macro plates which allow for accurate adjustment in two planes, it's very good for macro, but if you want to buy a new one it will cost around £300 (
view here)
You might also consider a single macro plate which is a lot cheaper, but only adjustable in one plane (
Here). You really will need a tripod which has the facility to angle the head to get it into the position you want.
These plates can be used for many other things such as QTVR and 3D photography.