I wouldn't recommend using pressure treated because the boards are soaked in chemicals and you get man splinters after a couple years. I also wouldn't recommend composite decking because each brand of composite decking has had many issues which would include mold + mildew build up, warping, cupping, and severe color fading. If you want an earful on composite decking problems visit:
http://www.squidoo.com/decking_material What I would recommend is a hardwood decking material like Ipe, Tigerwood, Cumaru, or Garapa. Hardwood decks will last up to 40+ years with low maintenance and will maintain their beauty with a simple UV Inhibitor applied so the sun doesn't bleach the wood (basically like sunscreen for your deck). They are naturally resistant to mold, mildew, insect attack, and decay. Also because hardwood decking has such tight grain it won’t splinter so its great to walk on barefoot for years and years.
Tigerwood is similar to Ipe but has more of an exotic look and your pretty much guaranteed no one in your neighborhood will have a deck made with it, it's exotic and a little cheaper than Ipe.
You can order any hardwood decking material from Advantage Lumber
www.advantagelumber.com They are the only ones I trust anymore, all of their decking is premium grade not select grade so there is no sap wood. Also if you get any damaged boards during shipping they replace them promptly which is important for a contractor like myself completing a deck project.
One more note you should opt for the Ipe Clip hidden deck fasteners so you don't have any unsightly screw holes in your deck