My local Borders closed a few months ago and I picked up a half dozen travel books for about 55% off of list price.
The deal that I bought these on was 40% off, plus another 25% off of that price if you bought 6 or more items.
What they generally do in these liquidation sales is to start out offering 20-30% off, and the deals get progressively better each week. It's kind of a crapshoot as to how long you can wait and still end up with a reasonable selection, because once the discounts reach 40% off overall, the selection seems to get pretty well picked over. In the case of my particular store, the shelves were pretty bare after the deal got to 40%, but then they pretty clearly re-stocked the place with excess inventory from the other Borders stores in the area that they had planned to have remain open at that time.