making the Back button in Safari take you back to a cached, post-rendered view of the previous page
This behavior is extremely frustrating. It is similarly annoying when Safari reloads a page because the previous copy has been reclaimed due to low RAM. Rather than flushing the previous version entirely, it would be much nicer for Safari to write the old version to flash. Reloading from flash would be much faster, and would also prevent the page content from changing on reload (e.g., Google Reader won't reload "read" items on reload).
This behavior is extremely frustrating. It is similarly annoying when Safari reloads a page because the previous copy has been reclaimed due to low RAM. Rather than flushing the previous version entirely, it would be much nicer for Safari to write the old version to flash. Reloading from flash would be much faster, and would also prevent the page content from changing on reload (e.g., Google Reader won't reload "read" items on reload).