I have been using a Bogen 3021 tripod for a while and am really impressed. When I got serious about photography, I soon realized that the tripod I had (a cheap Slik) was not going to cut it. It sagged under the weight of my F4s and was not stable at all. At first I was completely fixed on getting a Gitzo 1348 Carbon-Fiber tripod. I was reading books by B. Moose Peterson and wanted to get all the best equipment. Luckily, funds were a bit short at the time and spending $800 on a tripod was out of the question (not to mention $8K for a 600mm lens).
I searched around the Internet and found quite a few articles about the Bogen 3021. It was sturdy enough to support all my current equipment, was light, reduced to a manageable 25", and was under $100. After some thought I ordered mine from Adorama (along with leg covers and a carrying case). When it arrived, my first reaction was "Jeez, that's kinda small" but once I unpacked it and set it up I was totally impressed. I am 6'0" and the camera is just slightly under eye level with the three leg sections fully extended (center post not extended). It was stable and sturdy with my F4s and 300mm f4.5 lens (the heaviest setup I have right now). I like the quick connect system and the easiness of operating the leg locks. One thing that I kind of worry about is the plastic tabs that are used to lock and unlock the leg segments. In my search of the Internet I found a couple of people that have had the plastic tabs break. I can see how a sharp impact or prolonged use may break these tabs. There are metal replacements available and I may look into these in the future but for now I will just be careful with them.
The legs have a release that allows them to spread wider for those low to the ground shots. When you try to do this you will find that the center post will hit the ground first. I removed a section of the center post (I never plan on using it extended anyway) and that allowed the tripod to get a lot closer to the ground. If you remove the rubber stop at the end of the center post you will find a hex wrench attached to it. This is handy for removing the extension on the center post.
I took this tripod with me on a trip to Mexico and found it very easy to pack (it was small enough to pack into our hard sided suitcase) and carry. It sets up and breaks down quickly and easily. Just a note of interest, if you ever plan on taking a tour of any Mayan Ruins, don't bother taking a tripod. They don't allow them for some reason.
If you are looking for a great affordable tripod and don't carry any really heavy glass (a 400mm f2.8 would probably be a bit heavy for this tripod) I definitely recommend the Bogen 3021. Remember that this is a tripod only and that you will need a head also.