A second small 1/2 bath with a sink and commode can be convenient and nice to have since I want privacy when I use it. But I prefer to share everything else - a large single sink with ample nearby storage, a nice 6' tub that can fit two in a pinch, and a decent sized shower. But obviously this is a matter of personal preference of yours and whoever you share it with.

Funny about separate baths for keeping your mess from your husband...not how it usually goes, all my married friends complain about shaving stubbles, toilet cleaning woes, etc. and would love to have a separate bath so he'd be forced to keep his own clean with no detriment to her. Even though it would be unusual, I think lots of people would find 2 smaller baths appealing.