It's claimed that CF damps vibration better than metal. On the other hand, metal has more mass. I don't think it's a major difference, at any rate.
If you don't really need CF, get metal. CF is lighter, but that also makes any setup more top-heavy. I use my Feisol when its lightness is a benefit (also its size, as it's the same size class as a Manfrotto 055). My metal tripod is a Giottos 9371, a larger size. The hot/cold issue is minimized by its foam leg covers. I use it whenever its weight and bulk are not too much of an issue, as it is much less top-heavy with medium format equipment, and it has a tilt column which is excellent for macro. The tilt column is only useful in larger tripods, as weight off center quickly destabilizes smaller, less massive ones. I love the size of the Giottos for any work where the camera is tilted up, as I don't have to stoop and crane my neck to see through the viewfinder. If you are using a waist-level finder that will obviously not be an issue, and your tripod need only be tall enough for you to see the screen clearly. That's a big plus, allowing you to use a shorter (thus lighter and less bulky) tripod, or shorten a larger one for greater stability. When I'm having to walk a distance, I use my Feisol and a waist-level finder. Working out of the car or at home, it's the Giottos.
Like Fabrizio, I prefer a 3-way head to a ball, but the problem is the arms sticking out of most of them. I use a Bogen/Manfrotto 3028, which is not made anymore, but easy to find inexpensively ($40 for mine from KEH). The replacement is the 3D Magnesium, reasonably priced, and also without any arms sticking out. It's light and compact-very nice. If you get a ball head, spend the money to get a good one! I have not found a cheap one yet that I thought was worth the savings.
It really comes down to the conditions under which you are using the tripod. A friend of mine wanted to purchase a tripod that was better than the crappy overpriced aluminum legs/plastic hardware one she got sold to her with her Canon 10D. I recommended she look at the Slik tripods, because their quality is very good and they are lower priced than most other name brands, and a very good value for the money. She was going to be using it indoors, both at home with her little kids around, and at work with colleagues milling around. I explained that the extra weight of the Slik compared to some others was a benefit in that situation, as the setup was less likely to be knocked over. So for her, the least expensive quality tripod is also the best.
I sympathize with your analysis paralysis dilemma. I went through that. If you can check out any in person it will be of great benefit in your selection process. I was able to compare and quickly eliminate several heads and tripods just by testing them in the store.