Here's the brand of velcro I highly recommend - the original Velcro brand. So far its adhesive seems the most resilient to our local heat and humidity. I've tried a couple of other cheaper brands and even 3M and they all seem to fall apart at some point. Velcro brand however, I haven't had any problems with so far. Most, if not all of our troopers are using this brand.
It comes in 2 grades - Regular and Industrial. Both come in black and white...you may need either or both colors depending on your need. If you are doing a stormtrooper for example, you will need both colors.


The Regular type is sold by the foot and comes with 'hook'(rough) and 'loop'(soft wooly) sides together. Width is 0.75".


The Industrial grade is also sold by the foot, however the 'hook' is a different type supposed to command a stronger, more secure hold. The 'loop' portion seems the same as the Regular though. This grade is more expensive than the Regular and comes wider at 2".
What alot of us do is to buy the Industrial grade velcro, and slice it in half length-wise down the middle. Each foot would then yield 2 feet of 1" wide velcro that you can use. It ends up cheaper that way instead of buying the Regular.
You can get this from any HomeFix stores.