I have become a huge fan of the Aloksak bags! I purchased a bunch to see how they work and love them. I have quite a bit of my gear in an Aloksak bag, and use one as a map case when in the field.
Vacuum sealing works well too, but you can't reseal them in the field. I only vacuum seal stuff that I won't need to reseal (first aid items, batteries, powered drink mixes, etc).
Dry boxes are also great, but bulky and heavy. I use a variety of hard boxes to store my kit at home and in the truck or in transit when I am not carrying it. I am hard on gear, especially electronics; however I rarely break them when I am actually using them. More commonly my expensive stuff becomes paperweights because of damage while in my bag/backpack/briefcase/etc… So, pelican boxes have become my friend and I have a number smaller boxes that keep stuff like my PDA, GPS, Radios, etc dry and secure. While my GPS sheds it’s protective shell when in the field, my PDA always resides in its Pelican box when not in immediate use! To get to my point, only use the hard boxes when you need more than waterproofing or can afford the bulk/weight penalty!
Also, don't neglect the simple and cheap ziploc style freeze bags. They work well, just aren't as durable and resistsnce to tearing and abbrasion as the aloksaks are.
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"Trust in God --and press-check. You cannot ignore danger and call it faith." -Duke