I've been scuba diving for three years now, and have about 250 dives. This past spring I began working on my A license, and now have 66 jumps.
As Miss D said, and it's a point that I have made to other people, it that the scuba dive will last 45-60 minutes on average and the skydive will be a minute of freefall (what a minute though!) followed by a few minutes under canopy.
One of the big advantages of skydiving for me is that a lot of pre-planing and time is not needed. If I decide I want to jump right now, I can be at the drop zone in 30 minutes, on a plane within 15-20 minutes, out the door 12 minutes after that, and home about two hours after I left.... that can't happen with scuba.
If I had to pick just one, it would be scuba, but go out to Perris or Elsinore and make a tandem. I jumped at both those locations in October, and the scenery was incredible.