Great suggestions from everyone already. What is your budget?
@ 6ft, you would need a tripod that can extend up to approx. 60 inches or 5 ft. add 8 to 10 inches depending if you use a battery grip with your camera plus the ballhead in order to see through the camera's view finder at eye level. It is highly recommended that you do not raise the center column if the tipod has one. You want to keep the center of gravity low as much as possible. Bigger diameter tripod legs provides more stability and less vibration in most cases.
As already mentioned, the Gitzo and Really Right stuff are on the high end side for tripods, followed by Manfrotto. Induro, SLK, Bogen, and Sirui are on the more affordable tripods.
Ballheads and camera mounts should be considered carefully. I would suggest a bigger diameter ballhead since they provide a more sturdier hold and will less likely "drift" when positioned at an angle or when using a heavier equipment with your flash. Arca-type mount ballheads are the more universal quick release type mounts which are normally manufactured by Arca-swiss ballheads, RRS, Markins, and other manufacturers. Manfrotto and Gitzo has their own proprietary quick release mounts.