had to reply to this one...
as long as your kids (especially the little one) won't be crying for you or mommy, not guilty, go and have a great time!
your kids might have one of their most memorable and cherished weeks with the grandparents and they'll remember it like a vacation of their own. again, if that's the case, definitely, definitely go!
only you guys know your kids well enough to decide how they'll do without you, and that should be your #1 priority in deciding (meaning how *they'll* feel, not how you guys will feel).
i couldn't leave my kids - but we family bed and my kids are still too attached to me. but they're 4yo and 3yo, a very big difference from yours, and they're not used to me leaving them with anyone.
i have friends who leave their kids regularly for weekends and the kids do just fine and enjoy their own time with whoever is watching them and the parents can relax and enjoy themselves knowing the kids are totally fine with it. you guys won't enjoy yourselves enough to make it worth going if you'll be worried about the kids. that would be my case. it just wouldn't even be fun for me at this point in my family's life.
if you don't think the kids (again, especially the little one) will do great now, i'd plan it for 2 years from now. you can even start planning it now which is half the fun. it doesn't "have" to be on the 10th anniversary. my dh and i actually both forgot our 10th anniversary, and it came and went and we didn't do anything special. believe me, we'll make up for it sometime.
let us know what you guys decide. interesting thread!