Ask HN: How do you recommend I implement a dual boot PC?

Given the usual nature of discussions here, I was reluctant to post this question. However, given your undoubted experience, honesty and general helpfulness, I thought, why not? ...

I currently use windows 7, but want to move to using linux at home. I don't know the first thing about dual booting, but it seems to me to be the best option.

I like the idea of having two physically separate OSs. It just seems like a good idea though, I have nothing factual with which to base that opinion.

I'm happy to buy a separate hard drive. I also have no idea about what constitutes a better hard drive (other than the obvious more disk space => better).

I have played with VirtualBox, but that seems like a way to test and learn Linux, rather than use it properly.

I am going to be using primarily for software development, and in particular getting used to the environment which I use for my web servers. I also want to use the linux os for anything that is not explicitly better in windows (currently for me that means graphic design and occasional MS office dependent work).

I would be very grateful for any advice you may have.