* Wine is surprisingly good these days for a lot of software. If you only have an app or two that need Windows it is probably worth trying Wine to see if it meets your needs.
* Similarly, if gaming is your thing Valve has made enormous strides in getting the majority of games to work flawlessly on Linux.
* If neither of the above are good enough, dual booting is nearly painless these days, with easy setup and fast boot times across both OSes. I have grub set to boot Linux by default but give me a few seconds to pick Windows instead if I need to do one of the few things that I actually use Windows for.
Which you go for really depends on your ratio of Linux to Windows usage and whether you regularly need to mix the two.