Bill, where you been dude man?!?!?
Good to hear from you again.
I must say this post makes me quite sad...I've only played 36 holes in one day twice.
The first time was St. Ives in the morning and St. Ives in the afternoon.
The second time was Cascata in the morning and Cascata in the afternoon.
So, I have had no contrasting 36 hole days. Ugh! 
Mac, I've been shivering in the Idaho weather and handling Christmas for my five kids (ages 8 and under) the past few weeks which has sheltered me from the golf world. I turned 32 on Monday and my wife told me I needed to go on a golf trip somewhere warm so I'm ready to get back into the swing of things for 2010! Did I tell you I'm coming down to Atlanta at the end of May. We're taking the fam down to see my parents so we'll have to hook up for some golf while I down there.
I can't believe you've only played 36 holes in a day twice! You might very well die on one of my golf trips. When we went to Colorado a few years ago we alternated between 36 hole and 54 hole days for a week straight. One time in Montana we played 63 holes (two separate 18 hole courses and a 27 hole course)!