Doesn

Heck, that set was valuable the second it came out! That went like a brand new console!

Well if we're gonna do that logic, then I have one word: NINJAGO

Specifically every set from 2011 (1st series).

2507 Fire Temple?If there's a dragon, it's ON FIRE!

Those and the spinners.

I just glanced at the values for the "The Final Battle" sets and, whoa.

The three smallest sets (Kai's Fire Mech, Warrior Bike, Cole's Earth Driller) are already going for twice their retail!

I'm sorry, but I always find it amusing when people are willing to pay that much for something when if they only waited as little as a week or two they could buy it at normal retail. The annoying part is how those people are usually the first to complain about not having any money.

....Really?

What about 7397 Train Station & 7938 Passenger Train? Using Brickset's amazon comparison page showed these at up to 40% off on some of the european sites.

Not sure if this is really under the radar, but does the UCS R2D2 count? Most of the attention has been going to the SSD, DS, B-Wing, and even the unreleased X-Wing. I haven't seen very many forum topics talking about this in comparison with some of the other SW UCS. However, as Rich B said, if we keep talking about under the radar sets and what they are, they will cease to be under the radar! :-)