As soon as I read the overrated stuff, I keep thinking this is a thread for the most overrated series of 2006. (which is a tie between Garo and Kabuto IMO).
I actually only finished up Garo. I didn't keep up with anything, stopping with both Boukenger and Kabuto. I did however finally finish up Hibki and Dekaranger this past week... But I don't think either of those count.
If I forced myself to pick, I'd say Boukenger. Even though I only watched like 10-15 episodes, but it is one that I actually do plan on continuing. Kabuto, I only watched as long as I did because it was a Kamen Rider series, and I only finished Garo because it was short.