Will a External HDD work? I have a WD 1TB external hdd in which i have most of my stuff, i heard from someone that the hdd formatted for PC's or windows laptops dont work for MAC and it needs to be formatted again in another file system format, is that true cant i use my external HDD on a MAC pro?
You should be able to access most files that have a common app (Mac and PC) - the challenge will be saving any updates. Typically PC formatted external drives are FAT32, which will convert to the MAC, but not able to be write enabled back. The exception will be music and photos, they should be available for iTunes and iPhoto imports.
There are some HD's out there now that can run both Mac and PC platforms but they have to be partitioned for each platform. I want to say Click Free has one like this now. The best thing is to inquire with the manufacture before purchasing one. Or have one for your PC and one for your Mac.