I'm looking to buy a new, easy to carry, high-end tripod for my Canon 5D. Will be used mostly for stills, macros, landscapes night and day, portraits, groups and walking around shooting fun stuff. Lens run between a 50mm macro to 200mm-400mm telephoto.
I'll offer a few guidelines but ultimately it depends on what you intend to do with the tripod.
I own three different tripods.
Tripod #1 - My first tripod is an aluminum tripod (by Induro) and fairly beefy... this is a very heavy and very sturdy tripod. I teasingly say you could set off an explosion next to it and I don't think it would budget. What's great about this is that it's rock solid... it's not going to vibrate and translate those vibrations into blurry images if I take long duration exposures.
That's the good news. The bad news is... it's heavy. Very heavy. This is not a problem for studio use and when I did wedding photography it was no trouble to carry such a tripod from the car into the venue -- the distance wasn't very far. But let's just say that I wouldn't want to take this thing with me on any extended hikes.
Tripod #2 - I bought a very lightweight carbon fiber travel tripod (Benro Travel Angle). This tripod is very light -- feather weight. I sometimes clip it to my photo belt and walk around with it all day long. It really doesn't bother me and I hardly feel it.
That's the good news. The bad news is it's not heavy because it's carbon fiber (and rembmer ... carbon fiber has a lot of flex in it) and the leg tubes are thin. If the air is calm then the tripod is solid. But in a good breeze this thing will vibrate -- I need to use a self-timer or remote release because the act of touching the camera is enough to create some vibration in the tripod. I could hook a weight bag on the center column to help (but carrying weights defeats the point of it being light.) Still... this tripod has it's uses and I have no intention of getting rid of it. It actually probably gets the most use of the three -- I just have to take precautions when using it to make sure I don't get vibrations in my images.
Tripod #3 - This is another large tripod... and it's technically slightly larger than my 1st tripod (the heavy one). But this tripod is a Manfrotto carbon fiber tripod with a magnesium crown. So while it's large and sturdy... it's lighter than the aluminum triopod. It's still heavier than the Benro Travel Angel (ok... it's a LOT heavier) and it wont fit in a suitcase when I travel (the Benro Travel Angel will), but I like it for use around town as long as I don't have to carry it too long. It is very solid. That's the good news. The bad news... it's not cheap (well... none of them were particularly "cheap").
A good tripod usually allows you to buy a separate leg and crown (base assembly) and independently choose the head. I have a number of heads... three different sizes of ballheads and one gimbal head. I MUCH prefer the ballhead to the traditional pan/tilt head because you can adjust a ballhead much faster and even locking/unlocking the head to reposition is a much faster operation with a ballhead. The gimbal head is use with heavy lenses. It has the nuance of being able to neutrally balance the lens (center of gravity) so that even with very heavy equipment, you don't have to "lock" the head in place. I can leave the adjustments loose and swing the camera to anywhere I want and it will just "stay" put when I remove my hands -- very nice for action photography because it lets you point the camera like a tail-gunner.
Finding the right height:
To find the right height... completely extend all the leg sections to make the tripod as tall as possible. Now raise the center column/post on the tripod HALFWAY (not all the way). Place the head and camera on the tripod. If the tripod is the right height it should be at "eye level" if you are standing while using it. The reason for the extending the center post only half way is because if you're taking photos of high objects (think birds in high treeds) you'll want to raise the tripod. If you're taking photos of objects low to the ground, you can lower the column -- and yet whether you raise or lower you can continue to stand at your comfortable "standing" height.
My travel tripod isn't *quite* tall enough, but that's ok.
Incidentally... when taking portraits, I like to drop the tripod so that the camera is at "chest" level... NOT face level. This creates a bit of an optical illusion with your subjects.
A "tall" person thinks everyone else i short. A "short" person thinks everyone else is tall. But what clues you in mentally is that you gaze upward or gaze downward. By dropping the camera height to "chest" level, the camera "gaze" is just gently upward, creating the illusion that the subject is "tall" (whether they really are or not.)
Lastly... the number of leg sections is a factor.
Fewer leg sections means you can set up and collapse the tripod faster. But it also means the tripod is longer even when completely collapsed. However... fewer leg sections also usually makes for sturdier/stiffer legs.
More leg sections means it'll collapse shorter and possibly even fit in a suitcase. But it takes longer to extend all those sections and it may not be as solid.
These are "guidelines" because there are no "rules" -- but it gives you something to think about.
I have been very happy with my Induro, Benro, and Manfrotto brand gear. I looked very closely at Gitzo (they're a big name) but really could NOT see any real advantage over, say, my Manfrotto tripod (granted it's one of the better Manfrotto tripods and wasn't cheap -- but it was a couple hundred cheaper than the Gitzo tripod I was looking at.