TMNT is an odd thing for me. As a kid, I adored it, and I know I watched it a lot, had several figures(though never cared for any of the variant gimmick turtles), and of course loved the video games. Thought the live action movie was weird for some reason though, and preferred the second one(Tokka and Razar!).
Years later I tried to get into the original series again, and while I do agree there's a charm to the series, I haven't gotten more than a few DVD's. Somehow I remember it being more action packed than it really was.
I did check out the 2000's series when it was first on, but gave up on it after a few weeks, because I had no knowledge of the comics or what they were like, and I wasn't too interested in mutants vs. humans. I did pick up the entire Season 1 and Season 2 Part 1, but since I guess Season 2 part 2 is kind of rare I haven't continued on since then. That and the odd DVD releases have kept me from tracking them down.
These days I do recognize the original live action movie as being very good as well. I'm suprised how well it aged. The second film though is a bit too corny. Turtles III in hindsight is both better and worse than the second film: it didn't have the villians or the story(or the animatronics), but the action was better and the turtles were allowed to use their weapons. TMNT(Turtles IV) I find to be merely ok. It doesn't really leave much of an impact, in my opinion.