white iMac Lion blues

I am maxed out at 3gb RAM. That said, the screen on this 24" beauty is matte and as I am merely an amateur photographer it is worth having the nice screen and money saved vs a new system.

I'm not sure if a clean install is the right way to go or simply putting Snow Leopard back on. If I went back to Snow Leopard I would have to use my vault to add all of my newer pictures onto that drive. Is that hard to do?

Is a "clean install" hard to do? I've never done it.

Thanks for all of the help,
--
Russ