Well I am a tripod fanatic and IMHo it is perhaps the single most important accessory to your camera, if you like to shoot landscapes or pretty much anything else where you can get away with it.
I thought I would share a few thoughts on the Gitzo 5541 tripod and how I ended up with one.
This spring while on my way out shooting auroras, I tumbled with a snowmobile, doing something like 60km/h, not fun in it itself, and while the camera gear, the snowmobile and I (a little black, blue and shaken) fared without any problems my tripod were less fortunate:

Zooming out:

Now i have praised the velbon CF740 a lot, but the snowmoible crash killed it.
Now that gave me an excuse to upgrade my tripod, so here it is along with the velbon and my Induro A114 travel tripod:

Now sure the 5540 belongs to the largest 4 section tripods made and it does not come cheap either, but having used it for a couple of months I can tell you that if you shoot long telephoto, medium or large format or just value something that it will take a minor earthquake to move once locked down, then this is a tripod for you.
Ok it is large and with a wonderfully wide baseplate, that is more than big enough for a studioball. it is beautifully constructed, every single piece of it just feels solid, like in rock solid and coupled with a larger head like the studioball it holds even a medium format camera rocksteady in very windy weather.
I have to admit that compared to this baby even the Velbon seems like a flimsy piece of gear and it has been a pleasure to work with and will be for years ot come or next time I crash on a snowmobile with it
So if you need the sturdiest possible tripod, that falls into the treckable category, the 55 series from gitzo IMHO is the only way to go. Pricey they are, but you will love working with them in the field.
A side note and something to remember is that if you work in very cold weather with tripods and tripod heads, then put them outside for about half an hour before heading out and then tighten leglocks and head, otherwise it may not be a tightly locked down for as you thought indoor. Same when heading back in, loosen up leglocks and head a bit, otherwise you may be in for a really surprise when trying to use it indoors the next time

It will be locked down VERY tightly, I had to give my Studioball 15 minutes in the freezer to be able to loosen the panning nob again
