On how to keep something a surprise...give a list of 10 and allow him only to buy 3..or whatever number you pick. or write down something in a category like 'movie with hot hunk XYZ in it' most stars are in several. Or practice surprise that he got what you asked for
And my number one trick for surprise..forget what you put..make the list as early as possible and then forget about it. Just make sure you don't buy anything for yourself till after the holidays to avoid filling your own list.
On what to put if you really don't know, if you have kids or grandkids or even nieces, try asking for tickets that you would love to take them to....from some other relative not from the kid. Pick something you loved as a kid and would enjoy seeing them love. is better than not helping the giver IMO. (and might spark your imagination to think of tickets to a place you would like to go, without the kid) - course this only works if you live near the kids in question.
On books, if you really will only read them once (and many books I agree) try making it known you would love to read it, but know you would donate it, and couldn't ask for it cause the giver might be upset...if you keep talking you will find one person who doesn't mind and would love to give a gift that is also a donation. (I for one would do it-I already donate lots of gift books given to me...the house has no room for what I reread much less what I never reread)