If you're looking for older sherried whiskies, try the Aberlour 18yr. It is 100% matured in ex-sherry casks, and is quite good. It is $100, or close to it. If you want something a bit less expensive, you can try out the 16yr which is double-casked, making it a bit spicier. The 18yr is smoother, but the 16yr is still very good (and only $55!)
For a blend, I've heard good things about Usquaebach, and they have some more aged blends.
I assume you have tried the Johnnie Walker Green label? It is a pure vatted malt comprised of Caol Ila, Talisker, Linkwood and Cragganmore. Very tasty! I've seen it go for anywhere from $50-80.