Get the Premier Hat with the felt sweat band. Best hat hands down. In 07 the uniform vendors didn't sell them, not sure if they have picked them up. Also a little tip if you don't like the taller flying saucer look that the mens hat has(skinny guys look dorky in those, bigger guys look ok) get the female version. It's the same hat just a slightly smaller circle and it sits a little lower.

Everything else I would get from the vendors except maybe a belt and shirts.

If you are a OTS guy coming from another airline, just use your current shirts. The Abbots shirts suck IMO. pilotshirts.com will get you better shirts for way less money if you know what you like already.