I prefer Opera even without mouse gestures! The gestures are impossible on a MacBook with no dedicated right-click. Thing is, I’m posting this in Safari in XP because of the superior font rendering.
Konquerer sounds good. I want some of those things in Opera 10.
My top shortcut gets combines your 2, 3 and 4:
Search: CMD/CTRL+T opens a new tab, then type g, then type your search terms and hit enter. Who needs a separate search UI element?
Opera’s search inside a page by typing ‘.’ is teh hotness. I use it all the time.
I also like fast-forward: CMD/CTRL+right_arrow. Why bother finding the ‘next’ link on a multipage news story or in search page results?
Middle click to close tabs? sounds weird. Just use CMD/CTRL+W (or the close gesture)
Opera also has a great zoom. Just hit plus or minus. Or hold CMD/CTRL and use the scroll wheel. It resizes all page elements, except the odd unruly flash one. In the past this was bad because the pictures looked horrible at anything other than 100%, but now it’s pretty good.