Gift card, cash, or (if they’re a couple that would appreciate it) donation in their name, every time. That way they can buy what they want once things have settled down and they take stock of what they have and need.

There’s a pretty convincing argument, expounded upon charmingly in this book, that gift recipients get more utility (economist-speak for happiness, in this case) out of cash gifts: http://press.princeton.edu/titles/8972.html. (One for the Billfold book club? Are we still doing that?)