I use a Mac primarily for development. Mostly because I got pulled into making an iOS app (and Apple won’t let you develop on any other platforms than theirs for that, of course), but I really started liking it for other reasons than most people would say. I don’t really care about the design or the “apps”, but I actually really love the Terminal (or more specifically iTerm2). The Windows command line just feels… second thought. It’s not really a part of the operating system the way a UNIX terminal is. Now I could say the same thing about pretty much any Linux distro, and if the Adobe suite could run on Linux, I’d switch in a heartbeat. But for now, I’m sort of stuck with OSX, and I’m okay with that for now.
So anyways, when I do need to run Windows for IE testing, a lot of people recommend Parallels because “it’s the easiest” or “it’s the most Mac like” or whatever. But for me, I really don’t give a shit about any of that, especially if I’m forking over $50+ just to run Windows for one purpose. I don’t care about any other features except for Internet Explorer.
I run VirtualBox, a free open-source virtualization program for pretty much any OS. I can load an ISO of a Windows 7 install disk (or physically put the disk in), and it installs on a virtual drive and does EXACTLY what I need it to do, without throwing away money at something like Parallels. I can specify how much RAM it uses, USB support, shared folders with the host (awesome), and a shit load of other features. You can even output the OS on remote display!
This is by far the easiest/cheapest way to run IE on a Mac, especially when you can run things like IETester or IE10, which pretty much covers all of IE IMO. You could also install the IE Collection but it might be a bit overkill for most users.