I know the question has been answered satisfactorily, but I wanted to add that I use Propellerheads Reason 10, at least when don't need to make native .mod or .xm music files. It's paid, but very powerful. It supports VST instruments, like Chipsynth SFC by Plogue, which emulates the SNES sound chip, (and can even rip instruments from SNES games), Chipsynth MD by Plogue, which emulates the Sega Megadrive chip, and Refills like Chip64 by Ochen K. which emulates a C64 SID chip, an NES Ta0X chip, a Vic-1 chip from the Vic20, and the TIA chip from the Atari 2600. I love Reason for it's ease of use, and large variety of built in synths and samplers. I can quickly get a tune out of my head and into Reason. If you want to make chip tunes, but also might want to write a movie score, check out Reason!