If by digital objects you mean images we've been getting a lot of
mileage out of OpenSeaDragon  at the Library of Congress. You do
have to pre-generate the deep-zoom-files DZI  or you can implement
your own server side tiling code to do it on the fly.
As a space vs time trade off we generate tiles on the fly in
Chronicling America , since there are millions of newspaper page
images. But in the World Digital Library  we generate DZI files.
Chris Thatcher, one of the developers at LC has a fork of the codeplex
repo on GitHub , which we are applying some fixes to, since GitHub
is alot easier to navigate and use than Codeplex.
If you are curious here are some samples of the viewer in action: