Cleaning, decluttering and organizing

I'm in decluttering mode. OK, when am I not, but that's beside the point. The POINT is that I'm in decluttering mode to the point of searching on-line for new tips to help me out. There's something I've noticed about websites devoted to decluttering and organizing. They largely assume that the items you have fit your home, or will with a few adjustments, or that you can go out and purchase the latest organizational shelving and baskets and hanging rods and wall boards, etc. And I love the phrase "If you haven't used it or don't love it, toss it out."

I'm all for tossing things out. Really, I am. I have a stack of items by the front door waiting for new homes. I have a stack of stuff in the living room waiting for new homes. We've given away, sold or thrown out piles and piles of clothes, electronics, books, CDs. Magazines, kids' toys, and other items with limited life spans are regularly purged.
But (there's that but), all those organizational decluttering gurus don't account for the mobile lifestyle. What fits in this house, won't necessarily fit in the next. And something I don't use for 2 years here may be indispensable for 3 years next post. So how do I declutter beyond the "I hate this and will honestly never use it even if I have the opportunity" phase? Or beyond the "No child of mine will ever wear this outfit again" phase?
I feel stuck. I feel in my gut that we'll be over our weight limit with our next move and that honestly makes me feel like we're consumer gluttons. Granted, we are allotted the same 7500 pounds of personal items for a family of 6 as the 7500 pounds allotted to a single FS officer, so I feel a little better there. And I realize that I can't get rid of every stuffed animal or lego or DVD or photo album. And I don't want to put items like paintings or the piano in storage. We wouldn't have OUR home if we did that. And then there's the whole "memories" issue, with clothes no longer worn but purchased somewhere unique, trinkets that remind us of a great vacation, or useless bits that have a story attached to them.
So where's the balance between providing a comfortable and familiar home that reflects our globehopping lifestyle, and pruning out the items we just maybe might need later?