Wrath of the Lich King introduced a set of epic rings you could purchase in Dalaran for gold. While they were an obvious gold sink, they were legitimately useful, too. A gold sink done right, in my opinion. Rather than forcing us to pay to get our riding skill back or something like that, it was an optional (but very tempting) epic that you could drop the gold on if you want.
Patch 3.1 is actually making this investment even sweeter. For another 1000g (at Exalted) you can upgrade your current ring (if you purchased one) for an improved version, keeping it current and relevant. You need to trade in the old one along with the gold when you pick up the new one, so you can't wear them both at the same time unless you re-purchase the first afterwards. Not a smart thing to do, in my opinion.
If you want to see the stats on the new set of rings, just check out our little gallery below.