Just a quick note here, you shouldn't have to install ANY third party software for ANY optical drives.
Firstly, Nero for example is a suite of tools used for authoring disks. It's not aimed solely at enabling DVD playback. So the heads up probably isn't as warranted as stated.
Secondly, if your computer doesn't already support DVD playback, it's actually very easy and free to achieve. Just download and install a CoDec pack. I personally use the K-Lite Mega CoDec pack. It's a free pack of audio, video, encoding and decoding codecs. It's also very, very customizable. Simply installing it, following the prompts and using some logic to determine what you intend to use it for is all you need. You will be able to play back and create media files in virtually all formats. It also allows WMP to playback most, if not all formats (including apple quicktime vids).
So long story short, you can buy virtually any USB DVD/CD drive, without having to install any third party software at all. So long as the optial drive itself doesn't need a particular driver, it's basically plug, wait a few seconds, then play.