Tricky to choose and there is a good chance you might end up going through several (even pro grade ones) to find the one you like.
First off there is the manfrotto range - the 055XPROB - which is a popular choice, though myself I find that I dislike the setup. The centre column does shift into low mode very fast, but you end up with a long arm that gets in the way and also your tripod head will be at a 90 degree angle, losing you some motion control. Furthermore you generally have to keep the head close to hte middle, so it negates the point of having the extandable arm (which as I said tends to get in the way a lot).
I do know that you can put the centre column in upsidedown to get low angles as well and I know a photographer who does this, but I've not experimented with this method myself.
The older design manfrotto and existing Gitzo tripod legs have a removable centre column and you then bolt the tripod head to the middle of hte legs direct to get low, a setup I think I might end up shifting toward.
There is also the Benbo tripods that are different again:
Benbo Camera Tripods from Paterson Photographic
A single lock for all three legs and I do hear they are hard to get used to and often turn people away from them - but overall a solid set of legs.
Finally its not all legs but heads to - for macro I really really love the manfrotto junior geared head - don't let the junior fool you, its a heavy and very solid head, which allows you (slow) but ultra fine controls in each plane of motion - this is important in macro work where these tiny changes can result in big swings in the viewfinder image. For landscape, buildings, macro and other static subjects its an ideal head - for motion based subjects (like pets, birds and kids) its useless as it can't move quick without your hand on the pressure release - and hten you can only move one axis at a time.
Ballheads tend to make poor macro heads unless you go for the ultra high grade ones and high strength - even then you can suffer from ballhead droop when you move your hands off the setup - something not noticable normally, but very visable with macro work.
Regular 3way heads are ok, but not as fine to control as the geared head.
Also no matter what head you go with you will certainly need a set of fousing rails for macro work - to let you move the camera and lens back and forth on the tripod - needed to help aquire focus. This is far easier than trying to move the legs since you will be talking millimeters of motion which you just can't get outside with the tripod legs.
