Ok, I am going to install Win7 on my MBP, as I just bought a Sony Ericsson C905a phone and to flash (debrand it), I need windows to accomplish this . To do everything else, there are plug ins for Mac, but whatever. I have NEVER done this before. Upon my search, I learned that you cannot install an OS onto an external drive. This was AFTER i had backed up my external to reformat it for Win7. lol. So now my question is what uses the LEAST AMOUNT of space that i need. I wont be using the Windows side that much. I searched the forums and found some good info, BUT I failed to find any info on what would use the least amount of space. I know that running a virtual PC, you have to set a certain amount of RAM to run. In bootcamp, you do not. If the amount of hard drive space is the same, I will install it with Parallels (just waiting to buy, to see what would be better). I will be using next to nothing as far as computing power on the Windows side. My girlfriend has a dell xps workstation, so if i ever need a dedicated Windows machine, I have access to one.. Thanks for the help in advance!