Ive had more tripods than I can shake a monopod at. Ive had manfrotto, slik, giottos, redsnapper, benbo, cheap noname crap etc etc, but Ive finally settled on a Gitzo.
As to " what should I be looking to spend" I'd honestly say as much as possible. After wasting hundreds of pounds on all the above, I should have just bought a Gitzo from the start and been a happy bunny.
At least £100 for the legs, and then probably the same again on the head if buying new, but you can get great
second hand stuff. Both my gitzos were
second hand, and about half the price of what they were new.
I know its hard to spend that much on what is basicly 3 bits of metal, but when you are out in a muddy field and its lashing with rain, the last thing you want is to be wrestling with a tripod that wont play ball.
I want fast and easy to open legs, easy head controls and legs that stay where I put them and dont close on my thumb. One of my tripods almost ended up in a lake when I got so fed up with it, it was about to take a flying lesson. Most of all you want stability on any surface in any weather. This has been the hardest thing to find in my long and painfull tripod journey.
So Im a Gitzo convert, but Ive heard Benro are pretty close behind, there is an ebay store in China that someone will link too Im sure that gets good rep.