MASM (Microsoft Assembler) is the popular assembler for Windows. MASM is for 16-bit and 32-bit applications(x86). ML64 is the one for 64 bit sources (AMD64/x86-64)
NASM (Netwide Assembler) is the popular assembler for Linux but is available on Windows too. NASM supports 16-bit, 32 bit and 64 bit programs.
FASM (Flat Assembler) is available for both Windows and Linux. FASM too supports both 32-bit and 64-bit programs.
So I guess you would prefer choosing MASM according to your requirements.