i've spent $10 a bottle for Trappist Rochefort 8 & 10. 10 is one of the best beers i've ever had. i spend anywhere from $7-$10 a bottle for Dogfish Head World Wide Stout. i love that beer. i regularly spend $12-$15 for big bottles of Captain Lawrence specialties.
That is high for Rochefort, I think I pay $6.99 here but I agree very good stuff.
For me it was Westy 12 , we shot our 50th Beer Geek Nation episode with it and it was worth every penny. Paid about $25 shipped from a guy in Germany. Heres the episode if you have never seen this beer in action.