Opinions - Macallan distillery - which scotch to choose?

[GForce]

So I've tried both The Macallan 12 Year Sherry Oak and The Macallan 15 Year Fine Oak. From what I've read, these two are really the foundation of the distillery's scotch when it comes to bang for your buck. Connesseurs, from what I've read, have said great things about the 18 year Sherry Oak. It seems that it is what many consider to be a pinnacle example of The Macallan's quality and taste. I don't have a lot of money for my newfound interest in scotch, and once you get into the 18 year range you can expect to pay $100-$150 for 750ml of The Macallan, so it won't be often I can try a scotch that is this high in quality and age. The scotches I am considering are all from The Macallan distillery;

17 Year Fine Oak
18 Year Fine Oak
18 Year Sherry Oak
12 Year Sherry Oak Elegancia
Any suggestions on a good cask-strength bottle in this price range, from this distillery.

If you've had any of these, please let me know what you thought. I find it strange they offer a 17 year and 18 year Fine Oak variety, and since the 17 year is obviously much less expensive I'd really like to find out if one year really makes a difference in this line. Overall though I just want a good scotch from The Macallan, in this price range, that I can splurge on once to enjoy with some friends. Thanks.

Oh and here is a picture of my current Macallan bottles, although the 12 year is now empty and the 15 year has maybe three times as much as the 12 year does in this picture.