The important thing to remember about wedding gifts is that no fucks can be given at any point. Some of you folks are overthinking this. The purpose of a gift is to hook someone up with something they'll go crazy over, reinforce an existing social bond, and have a good time in the process.
Most of the time, unless there's a compelling cultural reason to give a particular gift such as cash, I don't. Instead, I ignore the registry completely, give what I want to give, end up with a bridal couple who adores me and is blown away by the cool gift, and spend substantially less than the other guests do in the process.
It's like being the guy from the Dos Equis commercial. "I don't always buy off the registry, but when I do, it's because I've already decided to skip your boring-ass wedding."
Not everyone can aspire to my level of coolness, of course. Over many years, I've developed what can only be called seriously badass skills. I use these skills to find out what would be an awesome gift for the bridal couple, and then to make that thing from scratch for a fraction of the equivalent retail price. A lowly non-badass, by contrast, is stuck buying off the registry like a bitch.
/trollage