This launch (given its 6pm time) has been compared to the iPhone launch, and obviously Apple coordinated with AT&T to get them stock (though not much) of iPhones in time for the launch at Apple stores. So despite past history, I'd think they'd be providing at least some copies to Best Buy, particularly the stores with Apple displays. That being said, I've been to 3 or 4 Best Buys with the little "Apple Stores" in them, and each only had a handful of copies of Tiger and other software titles. So I'm wondering more how many copies of Leopard they'd have than if they'll have them at all...and how long after they sell out it'll take for them to get more.
Edit: Of course I've pre-ordered Leopard, so my wondering is just curiosity 🙂