Josh,
I'm not sure what you mean when you say inverters are noisy. Small tacky inverters aside, the sort of equipment that is used for home solar electrical supplies provides a power supply that is dead silent. In most cases it is going to superior in wave form, superior in stability, free from fluctuations and free of junk interference [no, I have nothing to do with selling the stuff, I just use it]. Some inverters have cooling fans but they are usually installed somwhere that this doesn't matter [the fans aren't all that big anyway].
There can be disadvantages to DC supplies
http://www.audiocircle.com/index.php?topic=17661&highlight=batteries&sid=44b63243d94a3cc363e0919d81b0098fI'd be fairly confident that solar energy use will increase rapidly when people realize the degree of sophistication achieved now, particularly with regulation and management systems.
Solar panels have very long lifespans [30 years is quite possible] which have progressively lengthened. The weakpoint as far as stand-alones is concerned, remains the storage batteries. These are quite expensive and maximising their lifespan requires some care.
jules
