Lots of gimmicky stuff out there these days to catch a shooter by his wallet.
I think Lowlight nailed it with the tac table, bags attaching to rifles via rails, and those silly barricade blocks.
Some of the stuff in this thread, while bad (like recoil reducing bipods) were never really hyped up.
Quite honestly, the single most overhyped product recently for PRS was the Impact action. No doubt it's a great action, the hype behind that product was stronger then anything else out there, and by a wide margin. The internet was full of hyperbole and rhetoric when that action first came out, it was unbearable. When people would ask what action is the best/what to buy, people would just reply with one word responses "Impact!", because they couldn't explain why it was better then any other action (I think most responses were seeking validation on their purchase).
While the Impact is certainly a good action, and I wouldn't steer anyone away from it if that's what they had their hearts set on, it was overhyped big time. It's a nice rendition of the R700 two lug push feed action, but doesn't do anything better then a well timed any other modern tier 1 action.
Oh yeah, Curtis actions are also overhyped, but namely because the product quality is not up to par with other actions (and thus not worth the price).