Great Spy Novels for a Christmas present (Poll)

It's finally time to finish my Christmas shopping. My dad has always liked spy novels, buy rarely has the time to read them. Now he has more time on his hands and is starting to read spy novels again. I figured I would buy him at least one as a Christmas present.

Does anybody know what the best spy novels are? Any help would be appreciated.

I am not into spy novels but does this help you?

http://www.amazon.com/fifteen-best-spy- ... APV1YXTS54

http://www.crimefictionblog.com/2006/09 ... _nove.html

Ludlum for sure -
maybe the first 5-6 books by Clancy - he went downhill with co-authors after the first few books.
Follett is OK, but no match for Ludlum.

I selected other. While I really like Ludlum, I also like Frederick Forsyth and find his writing to be very engaging. Never could warm up to Follet.

Not on the list, but I really like Alan Furst, his writing tends to cover Europe from the 1920's to WWII. Love the history of that time.

Of the guys listed, LeCarre is my favorite.