Stormtrooper armor

Stormtrooper armor is the standard protective uniform of the Imperial Stormtrooper. The design is based on the armor worn by the Clone troopers of the Grand Army of the Republic, which itself is based on older Mandalorian designs. Stormtrooper armor is designed as much for intimidation value as protection, making them highly visible and distinctive agents of the Imperial regime.

Defense

Stormtrooper armor protects its wearer from many hostile environmental conditions: extreme heat, extreme cold, toxic gases, and even short periods of exposure to the vacuum of space. In addition to acting as a full NBC suit, it protects against physical threats such as shrapnel and blaster bolts. Due to the sheer firepower of blasters, however, the protection that any armor can offer is limited; the armor cannot fully protect its wearer from a direct hit, although it may mitigate the damage.

(I wouldn't mind seeing some evidence that supports the claim that standard Stormtrooper armor provides environmental protection. TESB seems to suggest that only specialized variants deal with certain environmental conditions).

Stormtrooper armour is specifically described as being impervious to projectile weapons, but this claim isn't entirely accurate; the white, rigid components are resistant to projectile small arms, but projectiles can still reach the wearer through the armor's joints.

And if if the armor were bulletproof (and evidence suggests otherwise, using ROTJ as an example), that's not to say that bullets wouldn't still kill the wearer (if the concussive force of wooden sticks and Han Solo's fist can incapacitate a trooper, bullets should have few problems). Further, the notion that it is in any way protective in the way that conventional armor is 'protective' for armed forces is rediculous:

The best form of protection is remaining unseen. Here, like in most other areas of the Imperial Army, Stormtrooper armor just really fails.

There appear to be zero camoflauging variants of the armor, all of it is extremely lustrous, bulky and easily identifiable. Enemy soldiers would have no problems at all in picking out Imperial Troops from bystanders and surrounding terrain - they'd just stick-out like a sore thumb (interestingly, this has become a real issue of interest in online play in SW: Battlefront).

Features

Equipped with built-in air filters, vision enhancers, targeting systems, suit environmental controls, communications gear, and 20 minutes of emergency oxygen supply, Stormtrooper armor offers various features to aid in combat situations.