3D molecular modeling software for Orgo?

Has anyone used/does anyone know of any 3D molecular modeling software for use in Organic Chemistry? Something that works like the ball and stick kits, but with a click and drag on a computer screen so as to save time? The programs I've looked at through Google seem to be pretty expensive…
I've downloaded a PDB viewer and files for it, and while helpful (it will display a molecule's enantiomer and allow you to rotate them, for instance) it doesn't really help with the reaction side of the thing because you can't start pulling things off the molecule and substituting/adding other things.

My school swears by the ChemOffice software put out by Cambridgesoft which include Chem 3D and ChemDraw. It is expensive but if you register with Chemfinder.com you'll get regular newsletters that include extra discounts on their software besides the academic discount. Our school made a deal with them to include it in with our organic textbooks (which came with a different program that isn't as user friendly). While I don't use the 3D much at home our prof uses it a lot in class and it is definitely very helpful. I do use Chemdraw a lot since we have to include structures in our word processed lab writeups. The office program includes everything you could possibly need for doing a write-up…chemfinder (you only get limited access to the full database thru the website, ie. if you need the info for something that is ambiguous it will only list the first few possibilities unless you have the full program), a tables editor, etc so if you're planning on taking more chemistry classes it seems like it might be a good investment to get the entire bundle but you can also buy individual programs on their own as well in which case I'd suggest getting at least ChemDraw and Chem3D.
Good luck!
–Jessica, UCCS

I don’t know if this would do everyting that you would like, but you can download “RasMol” for free. Do a Google search and you’ll probably find it. It’s also connected to some of the databases. Good luck!

Hi Jessica,
Thanks for the heads up on that. I went to cambridgesoft's website today, and once I activated the student discount and started looking at some of the older versions of the software (Chem 3D 5.0 for the Mac and ChemDraw Standard 8) in combination with the student discount the prices came down to managable levels. Ended up buying both those programs online and they are really quite amazing. Lots and lots of features!