From what I know, the spectrum of LED's really depend on the type. There are definitely full spectrum ones out there, and they are *extremely* energy efficient. Here's a link that talks about full spectrum LED's
The other nice thing about LED's is that they are extremely easy to wire yourself, I'm terrible with electronics, but I'd have no worries wiring up a set of lights for my aquarium. Here's a posting in the DIY section on someone who made their own. I'm sure you could post and ask how we'll it's going.