Heather : May I suggest you to try the "Clear Line 1.0.7 by Ivan Milaev".
It is a really flexible theme where you have a lot of possibility of side bars (1 left, 2 left, 1 left + 1 right ... etc). Just with one clic you can change from one to the other ...
I think it is the best I have seen in term of flexibility. I am using it on my pages (here) and it works very well.
If you don"t know a lot on the programming, just try it and you will enjoy. ;)
If you download and try it :
In the menu "appearance" (excuse me I have it in French and I am not sure of the good english translation), you select "Lateral bar".
Here you can select which kind of lateral bar you want (1,2, etc) on which page you want.
Below, there is the sizing of the bars, of the page, etc ...
If you decide to use this theme and have some question, do not hesitate to drop me a mail. I am using it since some months now and I know a little bit about it's possibilities.
PS : Nice pics ! ;)