The best replacement for optical drive is hard drive.

The best alternatives to optical drive are rated as following:
★★★★★  hard drive
★★  superdrive
★  super drive

Your alternative for optical drive is not listed? Suggest!
Speaking about optical drive, one probably shouldn't forget about mac mini.

Other search terms related to optical drive and their ratings are:
★★★★★ mac mini
You have in mind a companion for optical drive and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of optical drive in all years. Click on graph for more.
optical drive
hard drive
superdrive