how to get all those old DVDs into PLex?

You have 900 dvds and haven't ripped a single one of them yet? What have you been doing for the past 8-9 years?

No, you need to defeat the copy protection and other tricky things first.

After you have ripped the disc to a hard drive, Plex can play the resulting VIDEO_TS just fine, but, if you eventually plan to stream that video, you're probably better off ripping, then queuing up a bunch of those rips in Handbrake, then doing transcodes as a batch, letting it run overnight. It'll take you forever, though, since you have been asleep all this time, digitally speaking. Essentially transparent Handbrake presets for sd dvds were worked out years ago. If you might add all this video to iTunes at some point or might have iOS devices or Apple TVs down the road, best to transcode to the .m4v extension.

Going way back in time, most of us here used the exact same workflow to rip and transcode our dvds--you ripped with MacTheRipper and then transcoded with Handbrake. Then RipIt appeared on the scene, then blu-rays and MakeMKV. Now you have a plethora of good ripping and transcoding options, things like iVI in the Mac app store, for instance. I still use all of them, depending on the disc, its special features, subtitles, whether I know I want to watch it on an iPad, etc. Basically, there's no single easy and quick method that will suit everyone. MakeMKV works with standard dvds, so that might be a good place for you to start: MakeMKV will "rip," i.e. defeat the encryption on a commercial dvd (or blu-ray) and then extract the video and audio without any loss, resulting in an .mkv that can easily be watched with or served up by Plex. Keep that file as it is, or then decide to transcode it with Handbrake into a more iOS and iTunes compatible file.
Edited by chefklc - 7/26/12 at 10:43am

Will Plex read DVD ripped by RipIt?

Sure, XBMC and Plex can handle VIDEO_TS; with RipIt uncheck the 'use .dvdmedia extension' setting.

what do you mean, you dragged off...what did you rip them with? Can Apple's dvdplayer.app or VLC play them back?

If your goal is to have a copy of all your individual physical media stored on hard drives, so you can access whatever you want, whenever you want, from wherever you want, then you may find VIDEO_TS folders somewhat limiting: for instance, you can't stream a VIDEO_TS folder to your Apple TV or iPad, you can't "live convert" it with something like Air Video on an iPad, so if iOS devices will be a part of your viewing repertoire then it is best not to keep your only digital copy of something as a VIDEO_TS.

Anytime anyone asks what is better or is it fine, it's difficult to answer those kind of subjective questions because you have to decide that for yourself based on your priorities and the other devices you have.

Personally, I find navigating ripped dvd playback as VIDEO_TS a little awkward within front ends like XBMC and Plex, as a result I usually don't mind giving up the disc menu structure and using Handbrake or MakeMKV to give me the main feature as an .m4v or .mkv, but I don't do this with all discs, some that aren't that important to me, that I'll probably just watch once, I just keep as a perfect VIDEO_TS backup copy.

Something to keep in mind--a blu-ray, ripped with MakeMKV, then transcoded with Handbrake at a decent quality preset, will almost always look significantly better than that same title as it was released on a standard dvd--because you're starting with a much higher quality source.

I've always found VLC a little awkward, poorly maintained for the Mac and inconvenient to use as a first choice, frankly it's my player of last resort, and little else. I suspect the more you live with a real front end like XBMC or Plex, especially when it comes to remote controlling and changing settings on the fly from the couch with the little Apple remote or an iOS device, the happier you'll be.

.mkv is popular with the pirate/download scene, no doubt, but it is also (surprisingly) popular here with the Mac home theater crowd for a couple of reasons--first, it's a great way to access your blu-rays without any loss of quality, but second, it's a viable alternative to Handbrake for your standard def dads as well. You're right about Handbrake taking forever to transcode a dvd rip to the iTunes format of choice, an .m4v, but MakeMKV significantly shortens that process--if you're already starting with a ripped dvd, a la VIDEO_TS, it'll only take about 9-10 minutes to run it through MakeMKV and end up with a .mkv that a front end like XBMC or Plex can handle easily--and that an app like Air Video on an iPad can live convert and/or AirPlay to an aTV. I use both, keeping some as .mkv and others as .m4v, and sometimes I retain the original VIDEO_TS as well as a perfect backup of the disc. The notion that .mkv is somehow incompatible with a predominantly Mac OSX and iOS household is, well, folly.