Agile doesn't cut it.
>> Waterfall will serve you well if the requirements for your software never change, and are fixed. It's like making a circle of salt around your house: it'll keep the trolls out, for sure, but that's a lot of salt to blow if it turns out that trolls, actually, don't exist.
Total BS, try using agile on a very large fixed price, fixed function, fixed delivery date project and you are toast.
Little things like the software must be fully functional and deployed to all stores country wide before the xmas sales season starts and you have provided a fixed price quote and there are penalties nasty ones if you don't meet the deadlines.
Lawyers and 20 paces anyone....