I'm in the market again for a tripod and am looking for some recommendations. I travel a lot by plane and also move around a lot on foot, so I would like the tripod and head to be relatively compact and fairly lightweight, especially now that the airlines have all reduced their baggage allowances for international flights. Carbon fiber appeals, but I'm not sure if it's really stable enough (I have no experience with it). My heaviest camera and lens combination right now weighs about 4.5 pounds (about 2kg). I'd like the head to be very good at doing both horizontal and vertical orientations. I nearly dislocated my thumb last week trying to get my little Manfrotto ballhead to stay tight enough while doing verticals. It's the smallest ballhead, and it just can't handle the weight I'm putting on it. I'm very nervous when doing verticals because it looks like the head is ready to come undone and drop the camera at any minute. I don't want to have to fight with the head to get the exact framing I want. My budget is around $500 max. Your thoughts?? Thanks!