I would suggest getting him a gift certificate. here's why. First off, it is height/weight dependant which size board you will get. If you know his height and weight you can go to the shop and ask them what size and they can give you a range, but then within that range he will have his preference. Also, it depends what he wants to do on the board when you choose not only the length but also the model because different models are stiffer or looser for different use. For instance, I'm 6' and I ride a 168cm, pretty "stiff" Burton Canyon when I want to just freeride, which means just carving down the hill. I could go with a little more length if I wanted, maybe 172-174 but I like 168. When i want to do a day of freestyle - which is where you see the people grinding rails, hitting jumps, doing tricks, etc - then I ride a looser (more "pop" on jumps) 155cm board. Again, for freestyle my length range could be like 153-159, I like 155. Then there are the bindings to consider, whether you want more response (harder) or a less (softer). Freeride you want harder and Freestyle softer. If your husband has size 11+ shoes he might wanna get a wide model board otherwise his toes could drag if the waist of the board is too narrow. I am size 12 so i have boards which the model is specifically for bigger feet. Some models come in a wide option.
So, as you can see it is better for your husband to go into the shop himself and find something. If he is experienced he will know what he wants. If he has never ridden or only rented a few times then he should talk to the guy at the shop who will give him a basic beginner-intermediate setup, an all-around board at a length determined from a chart that matches height/weight to a length. Plus, even if you knew exactly what he needed you might pick something and have it be a perfect fit except he hates the graphic. Then he has to stare at the graphic he doesnt like every time he's on it and that would definitely suck.
oh, and plan on spending ~200-300 for the board, ask the shop person maybe they have some unsold 2006 models that they wanna get rid of since we're in 07 now and those will be cheaper. But if you also need bindings and boots then plan on spending 500 in the end.
NOTE** In Re Cocolemonjello's answer - Yes, you can take his height and weight and go get a board that *might* be weight/height appropriate for him, or might not. First off it's much more weight dependent than height. But moreso than height or weight is PREFERENCE. If he has never snowboarded before then he doesnt have a preference so you could go by this probably. If he has, then definitely do not because he has probably determined what he likes. Secondly, yes giving someone a push is a way of seeing whether they ride goofy or regular, but it doesnt matter because the gear is the same either way, the bindings just get mounted facing a different direction for each. Something Coco does not mention is shoe size - understandable being women don't have this problem, but as a guy with big feet I can tell you that if your husband has a shoe size 11+ his board options will begin to be SEVERELY limited. So check this before anything. But again, get a gift cert. or make sure you can at least get a store credit for the full value with a return - no restocking fees.