My last purchase was from RightStuf and I got:
Ai Yori Aoshi Vol. 13 (manga)
Yukikaze DVD Vol. 1 Limited Edition
Yukikaze DVD Vol. 3
Next I'm hoping to get the Heat Guy J DVD Vol. 7 (with Artbox) to finish my collection of that series, or the first Limited Edition Blu-ray/DVD of Kill la Kill.
I'd say most of all I probably regret not getting a lot of the limited edition DVD volumes that came with a series box in my younger years since some of those are getting quite difficult to find in good shape and at a reasonable price.