I thought to develop a pure platform-independant binary *nix is necessary. So I use Linux in VMWare to develop a bootloader for a training one month later to some of my colleagues. I would say it sucks! First, VMWare is too slow; Second, update the software packages in Linux is complex. Just because everything is configurable, everything is so messy. The complicated dependancy relationships will definitely stun you to faint. Maybe I'm just not a good Linuxor.
Then I met with GNU compilers. Actually I knew of it for a long time. But I looked down upon the GCC on Windows. The adequat params can help you a lot. You can configure gcc to any state you want. One of them, you can let gcc@win32 generate a pure obj file, then ld it without WinMain included. Remember, objcopy can help you escape from the Win32 runtime/apis totally.
At last, write your makefile with nmake's grammar.
Congratulations, man, you've set up the OS dev. environment on Windows 