Will I be able to run every windows program in linux?
 

Shouldn't a virtual windows running on linux allow that in theory?

Yes -- if the virtual hardware functioned identically to the real hardware which it almost does.

Yes, but you'd be much better off finding Linux equivalents of the programs. It's going to be slower, of course...you're running one OS inside another. And Windows isn't exactly known for being 'lean and mean'.

The only things that I don't have for Linux that I'd love, would be TurboTax and Quicken. There's nothing else I need that I don't have a Linux equivalent for.

As was said before You can ram all programs but the games probably will not work under virtual machine but U can use instead WINE.
Greetings
Artur