If anybody wants to root a refurbished device and wants to put android on it, you need to be looking for the nook tablets or nook colors.
Nook Tablet 16gb, has dual core, 1gb of ram, and the bootloader has been circumvented
Nook Tablet 8gb, has dual core, 512mb of ram, and the bootloader has been circumvented
Nook Color 8gb, has single core, 512mb of ram, and no bootloader
all three above tablets have cyangonmod ports
Currently Newegg has the 16gb nook tablet for $109. These were as cheap as $79 to $99 over christmas though from various sellers.
You get the blackberry if you want better speakers or you want to keep it running blackberry software.
You get the nook if you want to put android on it.
You get the nexus if you want a hassle free device which you plan to keep a while. It is $199 but it is worth it.