Using IPAD as photo album
Others have mentioned space limitations. I have a 16 GB model and it is enough for my needs. I do take a lot of pictures but the ones that end up on the iPad have been chosen as the most interesting. If your interest is in showing and sharing your pictures, it is much better to show only a small selection of your best work (and not just on technical terms). Otherwise, people get bored and lose interest. Also, the iPad resizes your pictures. I'm not sure what the final size is but they're smaller than the originals, that's for sure.
If you want to get over the storage limitations, the iPad isn't the best choice unless you jailbreak it or set up a web site inside your house to host your terabytes of pictures. I've used both methods and the jailbreak with XBMC combination satisfies me (the slideshow in XBMC is better too). There are some apps that let you access file shares on your network but I've tried a few and none of them are good at displaying pictures.
With the Balckberry Playbook, the ability to access files shares comes with the device. With the Xoom, you can use CIFS Manager which integrates much better than any other apps on the iPad with the same purpose.