And if you can buy online, you save on the sales tax (7-8%). Just make sure you know what you are buying though.
Aerostich sells lots of motorcycle related stuff www.riderwearhouse.com
and has a good no questions asked return policy.
Cycoactive.com sells mainly Touratech stuff.
If you are buying all your stuff from one shop at one go, discuss with the manager about a tax refund, its not as easy as Europe where you get a standard form to fill and your money back at exit but its doable.
careful with cloths though, most American shops stock 'common; American sizes so if you are below 36 waist, getting trousers may involve a little wait!
Port Harcourt, Nigeria