This guy has dood prices.CORAL REEF ECO-SYSTEMS
I also like this place.Aquarium Lights Hellolights.com
The cheap ebay are not soo bad either.
The LED's can be replaced, but you will need to know how to tear the light apart and put it back together, which anyone who can do a little DIY should be able to do. Make sure the voltage on the bulbs are the same though.