The subject says it all: CommandBurner is a freeware CD/DVD burner that has a nice GUI but also accepts command lines, making it suitable for .bat file use.http://www.commandburner.com/
I've used it for years, as part of my nightly backup strategy. I always keep a RW DVD in my drive, and via a .bat file I wrote, CommandBurner wakes up in the middle of the night and overwrites it with a backup archive of my most critical sourcecode and documents. Once a week I toss the DVD into a fireproof safe, in case the worst happens.
Call it Murphy's Law insurance: because I do this, I'll never need the disc.
Small, light, rock-solid, useful, and free... doesn't get much better than this.