I agree with all of the above. Don't waste time with cheap stuff. A tripod needs to hold up over time, be transportable, and most important, keep the camera stable during the shoot.
There are different ways to extend the legs (latches, rings and the like). Next you have 3 or 4 segments, with more segments usually less stable, but smaller when collapsed. You need to consider how tall you are and how tall you need the tripod to be. Really Right Stuff web site has a nice chart on its front page you can look at for this. No center column greatly enhances stability, and decreases the weight of this element.
Some tripods have a hook to hang additional weight to stabilize the unit- helpful during windy conditions. Some either come with, or have optional "accessories" that you may later purchase. These may not be important now, but keep an eye toward the future- like the leveling plate as mentioned by Neuro- it may not make sense to you now, but as you expand, the ability to use these items may become essential.
I totally agree that your head should be a separate purchase. This is a personal decision as the tripod legs. A lot of things go into this decision. One very important thing is the plate- Arca Swiss is my vote. Another thing is the layout of the tightening knobs. Be sure that they work for you, and be sure the head will carry the camera/lens load. Play around with it for a while to be sure you like it. I have a collection that look pretty but I hate.
I have a Manfrotto 190CXPro3 and it is a great tripod. I am going to get a RRS TVC-33 when I get my big white lens
So, be sure that the combo is easy to carry, easy to set up, and stable.
I have a stupid question, I have a Manfrotto 055CX3 and it came with a hook attachment; however, I'll be damned if I can figure out how/where this hook attaches to.
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