One good budget tripod I've encountered is the Slik 500dx. It's not light, but it's rigid. The 700dx costs more, but is taller. Also good.
Another good tripod at a good price is Giottos. I have a large aluminum one with a tilt column which I use for macro with medium format, and I have been pleased with it. Most models are available in either carbon fiber or aluminum, and with twist locks or flip locks.
I also have a CF Feisol that I like a great deal, though I wouldn't call it budget, except compared to a Gitzo. It gives very good value for the price.