If your goal is to be shooting cactus and other desert beauties, then I would heartily suggest Gitzo's Explorer tripods.
I don't own one, but almost bought one a few weeks ago after a lot of research for some particularly tricky run and gun video work out on some rivers. I discovered that the Explorer was unique for several reasons, namely the center column can be moved to many angles, and can also be inverted to mount the camera between the legs of the tripod, in other words very close to the ground.
Having your camera on a stable tripod very close to the ground could be a very unique way of shooting desert wildlife, it seems to me.
Also, all the legs lock independantly, at any angle. Consequently, you can spend more time shooting, and less figuring out exact lengths for each leg, etc. As I recall, it still has a spirit level on the legs, so if you had a bare bones head, you'd still be able to get the thing level without too much work.
Also, despite the center column being on a pivot (it's mounted just off center of the legs) it is very surprisingly stable. I anticipated that even though it was a Gitzo, it would not be particularly stable since it isn't your normal type of center column.....I was very wrong, and even though I really reefed on the thing in the shop, it was very very stable.
Unfortunately the carbon version is a lot more expensive (Gitzo carbon is among the best I've seen) the metal version (I think Gitzo's are mostly aluminum now) is not much heavier, on the order of a few ounces or so.
I heard through the grapevine that Gitzo will be coming out with an Explorer in their new Basalt fiber in the next few months, it might be worth emailing Gitzo or calling one of the reputable shops around the country.
I can't say enough good things about my little Gitzo, I've beaten the daylights out of it, and submerged it in water for video work, with a 10 pound camera. It was very stable, and after proper drying, it still works superbly.
Another option, though I am loathe to mention it is a new chinese company called Giottos. They make what seem like Gitzo spinoffs, and supposedly are quality products despite usually being half as spendy as Gitzo's. They have a set of legs very much like the explorer, and I believe the legs cost something like $110 or so, compared to B&H's Explorer price of I think $180.
I was lucky to get my Gitzo for very very cheap, but even if I had had to pay full price for it, it would have still been a bargain, because it will obviously still be in working condition many years from now....other tripods I have abused from Manfrotto, etc. fell apart after not nearly as much bad treatment.
Cheers,
L