I personally like to use construction adhesive. Urethanes are water proof and very strong.

Screws are nice, but there are some real crummy ones available, so go with high quality.

Screws will actually clamp up your project while your glue sets, but I always use clamps if possible.

I really like the Paslode products. I picked up an Impulse Nailer and that is really Sweet, and a great time saver. The nails are a bit pricey, but they have excellent holding power due to the adhesive coating on the nails.

Cecil,

I'll bet if you had my nail gun, screws would be a distant memory.