Will it hurt if I ask you to please give me a quote of your most favorite paragraphs from his ouevre?

The only thing it would hurt would be my copyright liability, since I'd have to quote the entire Hitchhiker series. My favorite concept was his creation of a method of faster-than-light travel through the use of restaurant mathematics: you know, the mathematics of dividing a restaurant check among the people at the table which defies all existing laws of science, nature and man.

Also, my husband is very interested in astronomy. Will he appreciate a copy of "The Hitchhiker's Guide to the Galaxy" for his birthday which is coming soon?

Hitchhiker is best appreciated by someone who has read some other SF first, since a lot of what Adams did parodies SF writing conventions. Still, I know people who have read Hitchhiker as an early foray into the SF genre, and they have enjoyed it quite well. And, since your husband is an astronomer, I'm thinking that many of the concepts in the books would have him rolling on the floor. Get it for him, and then you can read it!