I've never had much of a taste for Scotch Whiskey. Most of them taste like potting soil and campfire smoke to me, neither of which give me great pleasure. There have been a few that I would drink again though. All about at your price point, maybe a bit more.
Bunnahabhain, 25 year old. Not sure if you can get this outside of the UK, but it is quite good. Damn good actually. I had it when in the UK a few years ago and would most definitely buy it again if I ever see it. I think it was about 120 pounds when I bought it.
Glenlivit 25 year old. Very smooth and I'd buy it again. The 21 year old is also good, but I think the 25 year old is well worth the extra costs. The 25 YO is about $250, the 18 YO is about $180.
A good blend (gasp, not a blend!!!) is Johnnie Walker Blue. It is typically right at, or slightly under $200. I have not tried the King George, but heard it's quite good. The KG is over $300.
On a side note, if I were going to celebrate something, I'd probably get a good Champagne, maybe Cristal, and have it with a couple friends. An expensive Scotch Whiskey isn't really what I would consider a good 'celebration' drink.