In Safari, zillow.com simply mentions no support. With a current Webkit, you can get farther, but after searching for a location (e.g. Tucson, AZ), Webkit crashes when the site is loaded.
The crash you're seeing is bug 13984. If I go back to a nightly before that bug was introduced (the r21928 nightly), it appears to work fine. I don't notice any difference between it and Firefox. JD, are there any other differences you're seeing besides the crash?
Closing this as a dupe of bug 13984 since it no longer crashes and I notice no difference in functionality. *** This bug has been marked as a duplicate of 13984 ***
No other differences: things work well again (as well as in Safari 3.0.2).