I would suggest, starting with what you have now, and figuring out what you like about it and what you don't. For instance, I bought a cheap tripod off of evilbay about 4 years ago for 11 cents and $7 shipping. Overall it was OK - I learned a lot with it. I liked the size (a travel one), liked the leg clips, did not like the 3 way panning head with the handle, and the camera plate was clunky. By using it - and it worked fairly well until it fell apart, I found out what I liked and what would work for me.
So awhile back, I picked up a Benro (a Chinese knockoff at $160 from Amazon). It was the right size folded up for my luggage, not too heavy - about 3 pounds, but heavy enough to perform the job. Sturdy and stiff for its weight, well constructed, the price fit my budget, and I am pretty happy with it. I did compromise on the leg locks, since it has the twist rather than the clips, which I have now a slight preference for. It also came with a relatively cheap ball head (rated for 8 pounds of weight - which was fine since my heaviest load would be 2.75 pounds, so there was margin). The ballhead did not add any cost, since going in I considered it to be replaceable, however it did make the tripod instantly usable.
On the first couple of uses in the local area, it all worked out fine, the ball head was a bit of a pain with the levers to lock in the position. However, when I went to take a multiple frame panorama, I could not pan on a level horizontal plane. So I found I needed a new ballhead, which I was NOT surprised. This did show me that I needed not only a standard ballhead, but a panning ballhead, of which there are not all that many available.
A panning ballhead has the ability to pan above the ballhead rather than below it as most all of the ballheads are designed to do. This allows you to level the entire setup, and then pan on a level horizontal plane. So, I wound up picking up the Acratech GP Ballhead (note the last picture on the link and also the little video on its use - the ballhead can be used upside down making it a panning ballhead).
Acratech GP Ballhead*::*Ballheads*::*Acratech
To complete the entire setup, you will probably also need a way to release the shutter without touching the camera (even with a 2 second delay) - either a wireless (IR) or wired remote. These are relatively inexpensive at about $10 to $30.
Now you really do not need to go the expensive ballhead route. I did, because I wanted to do panoramas in low light situations (at night), essentially my reason for the tripod in the first place. The ballhead that may come with the tripod may be sufficient, or there are several threads on ballheads here (for somewhat heavy loads) in the $50 range.
that was my odyssey - hope it helps....