How curly is your hair? Is it frizzy?
My hair is extremely curly and can get frizzy if I don't use the right product.
If I'm using a gel, I use something pretty light like a Nexxus gel. Aussie makes a good scrunch gel too. Most of the time, though I don't use gel; I just use a product called Zero Frizz, which is a hair serum similar to Frizz Ease, only cheaper and I like it a whole lot better.
I used to use a diffuser on my hair dryer, but I really don't bother with it anymore. I put the dryer on low, scrunch my hair as I blow it just for a minute or two -- not enough for the hair to actually get dry. I leave it damp so the curls will stay well formed. If I really need for my hair to be dry, I'd go ahead and use a diffuser, but I haven't done that in ages. There's really nothing to it.