Before i set up my tank i was thinking of getting sand for my 100 gal, ive seen it in some tanks before and i think it looks great. i asked my LFS about it and they said it can give you problems some times depending on the kind of fish you have or are planning to put in it. Planning on puting oscars in my tank they highly recommend against it, due to the fact that when oscars get bigger they can disturd the sand with one flick of their tail and dispurse it throughout the water, causing it to get sucked up into your filters. now if you are using a HOB filter they said it can eat up the little plastic spinner in the motor and damage the motor very quickly. the same can be said for canister filters to a certain extent, i think the water passes through more media before entering the motor area but can still damamge it, and you will have sand build up in your canister and will have to clean it alot more often.
although i have not experienced it for myself, i trust my guy from the LFS (as far as i can throw him)

and decided against the sand and went with natural gravel.