I think I've paid $350 for BWI Concierge once. I've stayed at Poly Concierge too, but was able to get GV for $229 (oh how I would love that rate again!).
Anyway, I've paid $600/night for a GF honeymoon suite which was rack rate. There were no discounts or AP rates to be had so we had no choice. Great room though - once in a lifetime!
Now we stay at BCV b/c I love the BC and we can rent points and stay for $120/night. That really can't be beat!