I'm still trying to work out what to buy as well. One device that might be usefully employed between the tripod and the ballhead is a levelling base (allowing extra levelling capability) such as
Another solution is a Panning Clamp on top of the ballhead, such as
Images courtesy of RRS.
Note that I am not making any particular manufacturer recommendations here.
One article I have found very useful is Tripods and Ball Heads
by Thom Hogan. The only downer is that it makes a pretty convincing case for not scrimping when it comes to choosing a tripod and ballhead. I also note that whenever Gordon posts here on the forum on the subject he is fairly dismissive about lightweight tripods.
One final thought is that for panoramas you might want to consider an "L plate" as well as a levelling base. Here's a review of the Really Right Stuff L-plate
with some background information. The RRS web-site also has an interesting article on the subject here