Go to the last post in this thread: http://www.partyvibe.com/forums/community/27792-how-build-sound-system.html
Which should hopefully give you some idea of where to start. If you’re going to use it outdoors, then the very least power you should be looking at is 2K – if you’re buying the speaker boxes pre-made then up this to about 3-4K as a minimum (outdoors requires much more power than in, and if you under power it then you will in all likelihood end up blowing things when your DJ’s try to get more out of it than it is capable of giving.)
As for generators – make sure you have one powerful enough to run all you are trying to – take the RMS power ratings of the amps and double them, then add another Kilowatt for the decks, mixer and other equipment. Run your lighting from another power line to your audio (strobes are regular offenders for tripping circuit breakers, and you don’t want your amps turned off like this if you can help it).
Again, underpowering is likely to end with blown equipment – especially if you use petrol generators – diesel generators supply cleaner more constant power, as well as being a lot safer to refuel etc, so always use diesel if you can (I refuse to run our rig from petrol these days – if there’s no diesel genny then there’s no party…)
If you decide to buy pre-built, look for a complete system rather than a collection of mix and match parts – system builders can get a lot of extra efficiency from the parts that you won’t get by mix and matching. And if you’re looking to do DnB then try and get a system with Fane Colossus on the bottom end :bounce_fl
