Donate to the shelter where they got the dogs from. You can do it in their name or their dog's name. This way other great dogs can go to other great families.
It would always make me cry when people mentioned my deceased pets and I hate being all weepy in front of anyone so cards were nice for me-showed me they cared but I didn't have to have a Lifetime moment with them. And I have mentioned this before but Dog Heaven by Cynthia Rylant is a wonderful book.
That book is awesome. Also, Angel Dog or Dog ANgel? I can't remember which way. Kaci read this at my house...isn't it great?
Well, I ended up getting a nice card...and brought along my friends the Captain, Jaeger and Absolute. Another friend was telling us about how after her dog was put down her vet sent her an imprint of the dog's paw. I'm hoping SIL's vet does this as well, as it sounds like a really great momento to have.
After I lost my kitty last year, a friend brought me a small azalea for my yard in rememberance of her. Everytime I look at it now, it reminds me of her. I thought that it was very thoughtful.