#4. "RE: Lightroom 3 (64-bit)?" In response to Reply # 0
The question related specifically to "... from Adorama or B&H ..." -- nobody (including me) dealt with that.
Not having purchased from a 3rd party, I cannot be 100% sure. However, once you have a license you have a license and you should be able to download upgrades etc, so I would think that what you purchase from there would be the full install -- and yes, that includes both 32 and 64bit versions.
#5. "RE: Lightroom 3 (64-bit)?" In response to Reply # 4
For obvious reasons, I can't speak for the specimens bought from Adorama or B&H, but I don't think there is more than one version around (for Windows). A few weeks ago I bought a Wacom Intuos 4 tablet that was advertised as having LR3 to go with it. The disk was marked "for bundles only", and I posted a question on Adobe forums if it was ok to split the bundle, considering the fact that the salesperson said it would be ok, and only after making the purchase I realized that it was marked for bundles only. An Adobe employee replied that the only restraint is my concience, and there are no technical restrictions. The only thing needed is the serial number on the disk. You can, and should, download the current version from Adobe download site and install that using the serial number you bought.
The most likely explanation for the low price is that everyone is expecting a new version in a few months, and Adobe wishes to expand the installed user base.