Rebooting the phone doesn't close anything from the task bar. And I like it that way. Plus it goes to see that those apps aren't really running in the background.
Back to the original subject of this thread, I have the same build installed on my iPhone 4 and safari doesn't behave the same way like on the iPad, as in the search box doesn't come up when opening a new page.
About to install 4.2.1 this morning, so I'll check to see if it does the same thing.