I've actually been going back and rewatching all of Star Trek, from the beginning. I've actually watched all of the original series, Next Generation, and Deep Space 9 in the past, but not Voyager or Enterprise, and I think I missed one or two of the Next Gen and reboot movies. But it's been over 5 years since I watched the shows last, so I decided to start over and watch them again. I'll have to buy some DVD sets to actually watch all of them, since I don't have Voyager or Enterprise yet, and I doubt if I'll bother with the reboot movies.
I recently finished going through the entire original series. I made notes about which episodes were so bad that I have no desire to ever watch them again if I go through them all again in the future. Let's face it - that show had a few very good episodes, and quite a few very bad episodes, with maybe half that were in between.
I also watched the first movie, which was actually better than I remembered. The plot was boring, but in the context of having just watched the entire original series, I appreciated the artistic merits of having a big screen budget and MUCH better fx. Also, first appearance of Klingon foreheads and the Klingon language. Still not a very good movie overall, though.
Next up is Wrath of Khan, which is a big step up. I'll probably finish all 6 original crew movies before moving on to Next Gen.