Why would you Dual boot, when you can use VBOX or VMPlayer that works equivalently equal in Full Screen Mode? I use it. Works fantastic.
I agree, I use VirtualBox, VMPlayer, and Virtual PC, and they work great for trying out other OS features. However, if you are doing any "real" work in Linux, you'll probably need more than a fraction of your machine's RAM & CPU. These virtualization techniques are horrible for that - you're better off booting straight into Linux and only running 1 OS at a time.
I didn't have any issues when I installed Mint 12 but I have used EasyBCD to fix boot menu issues before.
They have a free version st the bottom of their web page.
I would stay away from using EasyBCD - I've had some issues with it before that were only correctable from the command line interface in Windows Recovery mode. Windows' boot manager isn't very good at handling an OS that isn't Windows. To get a seamless dual-boot, first install Windows from boot, then Linux from boot. Your Linux installation should install the GRUB boot manager, which is a lot more stable with Linux.