If someone gets pissed at you for your OS choice, you can only assume that they are way to invested in their current choice. This is even more true if they have a problem with you dual booting.
The one thing I would suggest if you decide to dual boot is to get a second hard drive. Hard drives are cheap these days. This way you can unplug your your Windows drive when you install Linux, and unplug your Linux drive when you install Windows. This means you will have 0% chance of having any kind of GRUB/LILO boot problems caused by dual booting, even when and if you need to reinstall one of your OSes.
You can then use the BIOS boot selector to pick which drive you want to boot to.
