My wife has a laptop with reasonably little hard drive space. I have a laptop with plenty. We have a desktop machine on Wifi that has plenty as well. We have a couple of different cameras which may be connected to my and/or my wife's laptops in no particular order. My laptop runs Ubuntu, my wife's runs Windows 7, and the desktop machine is Windows 7 as well.

I'd like some way to give everyone access to the photo library, including the ability to add photos (with duplicate import detection), tag photos, rename photos, etc. I'd rather run locally than rely on a web service if at all possible.

Any ideas? I'd lean towards some kind of shared drive on my desktop machine, which gets backed up regularly off-site. I could get Windows and Linux compatibility with Samba/windows file sharing. I'm just not sure if there's some program we can put on everyone's computer that will handle tagging and reorganization well with multiple users.

Warning: Dangerously cute photo of my new baby attached. [attachment=1627:DSC_0026.JPG]

Get a network storage device.

For example, We use the "MyBook World Edition", a 1TB drive that hooks up to Ethernet. You can extend the space by attaching USB drives, or paying more for the 2 or 4 TB edition. It offers media server access to x360, ps3, and tons of other devices. Of course it isn't the only cheap NAS out there, so shop around to compare.

Have your systems all automatically dump the files in a directory on the NAS device under a common folder layout.

This works very well for us.

On the device they are all under \Photos\{date}\.

What good solutions are there (if any) for tagging images such that the tags are part of the files themselves and thus show up on various computers? Am I pretty much stuck with really long filenames?

I name the albulms/folders after the date and maybe the subject.

\YYYY-MM-DD Some thing I did that day
\PIC0001.JPG etc.

I thought you said you were using Windows 7?

Windows Photo Gallery, available since Vista, has tagging functionality. You can set tags either as meta-information in the file or at the directory level.

There are quite a few types of tags, including "people tags" that are much like those in Facebook, "geotags" similar to various map systems, plus more traditional "descriptions" and "captions". The tool has a reasonably good AI that will auto-detect faces and gets pretty accurate at tagging the correct names in photos.