Mac: Even with Apple's Boot Camp, sharing files between your Mac and Windows partitions is clunky at best. Paragon NTFS is one of the better tools for doing it, and if you're still on Snow Leopard, you can now snag it for free.
Paragon NTFS makes it so you can easily access your Windows partitions so you can transfer files, delete files and everything else you'd expect. It's also pretty quick and once it's set up looks just like a native file system. If you're on Mavericks you'll need to shell out $US20 for the software, but Snow Leopard users can snag it for free from the link below.