The only ones I can stand are the British bundle (actually like the eq a lot), blue tubes tempo delay (with the 3 delays) and the distortion (blue tubes valve driver) is actually pretty nice as well.
I really don't like the blue tubes reverb or analog track box (don't use them, but own them).
The absolute most worthless one I bought was the ASP Studio Channel. What a piece of shit. It just didn't do anything I would expect and everything seemed to do nothing or the effect was almost completely nonsense.
If you want to hear any let me know, I'm bored enough to post some examples.