Ally,
I'm going to ignore your exclusion of Gleneagles for the list and assume that you were talking about the Kings, or Centenary/Monarchs/National or whatever its called this week, and therefore holes from the Queens could be listed. That being the case I would nominate the downhill par 5 on the way out, and the two long par 3's and the short par 4 on the way in. Possibly the best holes on the estate.
Prestwick St Nicholas - this course seems to get overlooked on this site and for the life of me can't think why. Actually I can, the proximity of Old Prestwick tends to overshadow what is a better course. The first is a shortish par 4 (c.350 yds ?) played through a couple of dunes, the second is a mid iron par 3 over a sea of gorse to a plateau green and finally the 16th (I think) is a par 4 that defies description, it just needs to be seen.
Darley, Troon there are a couple of realy good strong par 4's but for the life of me I can't remember the numbers.
Monifieth - lovely wee par 3 on the way in. Pines trees, heather, gorse. Picture postcard stuff.
Rich, agree with your comments on the Serpentine at Murcar (7th ?).
Sorry I'm rubbish with the numbering.
Niall