
To give some context, the person who sent the message is an amateur photographer interested in long-exposure photography and self-portraiture.
These are pretty much the only times I use my tripod, too, as I much prefer cranking up the ISO on my cameras over locking myself to a tripod - I'm always on the move and I find that for my subjects, in the time it takes to properly position my camera on the tripod the moment is gone.
I'm a run-and-gun kind of guy.
That said, there are situations where tripods are absolutely critical. Three that I can think of off the top of my head are
1. Long-exposures where it would be unreasonable (or physically impossible) to hand-hold the camera steady for the duration of the exposure. One rule of thumb to remember is that the exposure duration should never be longer than the reciprocal of the focal length (e.g. 1/200th of a second at 200mm). Also note that a shutter speed of 1/60th of a second is required in most cases to freeze moving subjects (like people at a party), with shutter speeds increasing in speed as motion quickens.
2. Using long lenses that cannot be comfortably carried without support. In these cases, a monopod can be used effectively, but there are other options. When shooting surf, for example, specialized Wimberly tripod heads allow a great range of motion and permit fluid operation.
3. When you want to include yourself in the photo! Photographers make great subjects, too, you know!
Anyways, on to my answer.
I personally use Manfrotto 055XPROB legs with a Manfrotto 322RC2 grip-adjust ball head.
Manfrotto 055XPROB
In all honestly, I couldn't tell you the FUNCTIONAL difference between many tripod legs available today, but I do know the features that guided my selection of the 055XPROB legs.
They are pretty light weight, but not as light as many of the carbon models available. I don't see the value of an ultra-light (and fragile) tripod for my purposes.
Another feature I like on my tripod legs is the built-in level. This allows me to set up my tripod on uneven surfaces while maintaining a level plane from which I build my picture.
My favorite feature of the 055XPROB legs is their ability to GET LOW. With a push and a pull I can shift the main shaft - the one that the camera sits on - to a horizontal position. I have used this feature (in conjunction with the legs at the widest setting) countless times to achieve a perspective that is unique and unattainable with standard tripods.
Manfrotto 322RC2
I'm a big fan of this head. I find it's controls to be very intuitive - I just grab the handle, give it a squeeze, and am free to position the camera however I like. Once I release the "trigger" everything locks up tight and my camera is secure. I trust this head with all of my gear.
I have used regular ball heads, but nothing is as simple as squeezing a handle.
Additional features of this head include adjustable friction (to allow easy operation with light set-ups, or to secure the big guns), and another spirit level (because one is just not enough!). This head uses standard quick-release plates to mount the camera.
I admit that I do not have experience with the sophisticated and precise geared heads, but what I have works perfectly for me, so why spend any more money on something I might not even like!
Let me know what you guys use!