Phil Wahba's article in ABC News / Money points out (a) that Borders outlets overlap substantially with B&N and (b) the leases on Borders stores are long, which suggests they could go out of business first - leaving a cannibal boost for B&N.
We should also remember that in addition to the high street presence, B&N have 637 college stores. Blackwell's has done famously meeting the text needs of generations of Oxford University students and I'd have thought the college connection will continue to be much to B&N's advantage.
Further, the Nook Color is getting favourable reviews e.g. here and here , and this says they expect a million sales by year end.
I don't tip shares - but I'll keep an eye out for B&N news and wouldn't be surprised if the shorters get a surprise in 2011.
DISCLAIMER: Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog.