Stamps...what are you going with? Rubber stamp and ink pad? Self inking?
I got self inking. You will be thankful if you have to stamp large drawing sets.
Self-inking all the way. So much easier to use. I also got the extra digital image. So if working with large drawing sets, the seal can be applied that way and save a ton of stamping.
Colors? Red? Blue? I had a colleague tell me he uses blue, so it would be easy to spot a photocopy vs an original. What about imprint seals? Anybody actually use them? So many options. I really want an imprint seal just because it's so cool, but I'm not sure that I'd actually use it nearly as much as a normal stamp.
Knightfox -- did you create an Adobe Signature and imprint the digital seal with that? So it's digitally signed and locked via some adobe verification? Or do you just paste the jpg onto the drawing?