External USB optical drive. That way keep it in a closet or something until you need it, which will be very rarely. I ended up ditching one optical when I went to p67 cause my board doesn't have IDE, and I still have only one game that needs an optical disk. If you have a fast internet connection, I wouldn't even bother with the USB because you can download disk images pretty quickly for most programs, or just buy on steam or for download elsewhere.
My laptop is a Macbook Air, and I thought originally not having an optical drive would hold me back a lot. I almost bought the superdrive. I honestly have only once in 2ish years of ownership wished it had a CD drive, and that was because I wanted to reformat the computer. I just finished perfecting bootable USB on my desktop computer, and now that I have a bootable USB disk, I feel a weight lifted from my shoulders