Over on his blog, Our Naples Adventure in Shorewood, Illinois!, (link in the My Blog List on the sidebar) homeowner Jim has an excellent write up on installing a new sump pump with battery backup in his basement. While we don't have a basement or sump pump in our current house I speak with some experience that this is a must-do upgrade that anyone that does have one needs to make.
At our old house we had a crawlspace. Due to the high water table and the sloping of the yard we had a sump pump in the lowest corner under the house that pumped the water through PVC pipe to the ditch that ran alongside our yard. When Hurricane Irene moved through central Virginia in August 2011 it knocked our power out and with it the sump pump. The next morning we awoke to six or so inches of water in most of our crawlspace. Due to improper grading under there it had backed up onto the vapor barrier and we had to poke holes in that to get the majority of it to drain away. The power ultimately came back eight days later.
While we got lucky that the water didn't cause any actual damage if I had a basement I'd do what Jim did for sure. (Or buy a generator to power the pump.) I definitely would not want to risk the chance of flooding inside. As it is at our new house we have a French drain around the perimeter of the crawlspace that drains via gravity from an outlet in the front yard near the curb. There's no need for a sump pump and with the prior experience at the old house this was a big plus for us here.