Weeds are a fact of life in gardening. You'll have them either way. :) However wasting good, proven-to-be-productive soil would be awfully difficult for the gardener in me to do so yeah I definitely use it. As you move the soil many of the clumps of weeds should be easy to pick out and toss.

Dave

Weeds are self-seeding, so if you do a decent job weeding this year, next year will probably be easier. If the seeds are getting blown in, putting in new soil isn't going to help in the long run. If you don't do decent weeding, it's going to end up filled with weeds as well. The weeds aren't a property of the soil. They've been added to it. If it works, use it.