Perhaps today's title is a bit misleading, so allow me to get to the point: These are all really frakking expensive achievements.
We talked about this two years ago in OverAchiever: Straight to the poorhouse, and everything on that list is still valid with the exception of Dual Talent Specialization (once 1,000 gold and now 10). Back then, my criterion for what constituted an expensive achievement was anything that cost 1,000 gold or more. These days, there are even more ways to empty your wallet in pursuit of points, but I have to wonder: Is 1,000 gold a lot these days? It's still a lot of gold, but is it a lot of gold? That's up to you. I think it's just enough for most players to consider something a serious, if not necessarily crippling, purchase. But don't worry: If you're looking for crippling purchases, I've got those here too.
This list won't necessarily cover every expensive pursuit in the game for the simple reason that not all of them are achievements, but if you've been sitting on a pile of gold wondering what to do with it, why not go get yourself some extra points? Who doesn't love suddenly finding themselves bereft of funds?