I saw T-3 yesterday. I enjoyed it for what it was knowing full well it wouldn't compare to the original (nor the sequel, for that matter). I didn't care for the actor playing John Connor though, so unless he gets some likeability, T-4 won't be much fun for me. Oh, okay- it'll still be fun with the effects and all- but it'll be sad not to have any characters left that I actually want to survive the movie.
As for Jason v. Freddy... Yeah, I wouldn't mind seeing that mind-numbingly stupid movie. In fact, I'd probably sort of enjoy it...