Gotta give Command Strips a plug. We've added a few pictures and momentos to the hallway walls and Command Strips does a great job.
Also, DW and I were discussing hanging some family pictures. Discovered some very nice digital, high resolution picture frames in the $35 to $55 price range on Amazon. We really like the one that has the motion detector -- it turns off if no one is in the room but turns on when you walk by. Holds a ton of pictures which are loaded to the device via USB, SD/SDHC card, and from your smart phone via a 10mm connection. Oh, and IIRC, the frame is rechargeable though a USB connection so there's no changing batteries.
HTH