If you want great high quality photo-realistic images RPC (Rich Photorealistic Content) is worth taking a look at and try. There are several free ones. Take a look at Archivisions website for AutoCAD & AutoCAD Architecture Users. Registration is needed to be able to download them though.
Via IMAGINiT Architectural Solutions Blog that also mentions there are 500 free Multi-View Blocks for AutoCAD Architecture 2008.