IMO, having good medium wave [AM] performance is a MUST. FM is line-of-sight, which limits its usefulness in an area wide disaster. AM, on the other hand, has a much longer range because it can bounce off of the ionosphere. This is why you can pick up New York or Atlanta from Northern Ohio on a pretty regular basis. Weather bands? I have had no luck with cheap weather band radios - but if I listen to Chicago, or Detroit, I'll know what my weather will be in a day or two. And if my area is hit with a disaster, I'm sure Chicago, Detroit, Pittsburgh, Cincinnati et al will be talking about it.
Shortwave might come in handy if you live along the Canadian border. IIRC, the Canadian Broadcasting Corp. still uses SW for normal internal broadcasts, given the size and population density of our neighbor to the north. Disasters have absolutely no respect for international borders, and if something affects the border region, I'm sure they will talk about it.
Also, never underestimate the entertainment value of radio - SW or otherwise. In a disaster situation, keeping up morale will be an important consideration. An evening listening to, well, CBC for example, will brighten up the mood.