I personally can't use any browser except Firefox, because I can't stand the web without adblocking.
It, like all Cocoa apps, supports some of the emacs key-bindings out of the box. CTRL-a, CTRL-e, CTRL-k all work as expected when editing any text.
If I double click on a word to highlight it and then right click on the highlighted word I'm able to look the word up in the OED resident on my computer. I can do this amazingly fast. And I do it all the time.
I have a huge bookmark collection. And Spotlight can search it.
I can check my spelling. Have it highlight misspelled words if I want. Bring up a spell-check dialog box, etc.
There are probably ways to get all those features in Firefox but Safari is the path of least resistance.
Point taken on OED vs. OAD. Regardless it's a fine dictionary and lookups are really fast.
Using the services menu to look up words is a good idea but I'd need to have a compelling reason to go though the effort of retraining myself. Plus the process will never be as fast and natural as a right-click.
The ad-blocking advantage of Firefox/Camino is not a compelling reason for me personally (at least now). So it's status-quo for me unless something changes.
http://pimpmysafari.com/plugins/?c=Adblocking
However, don't you think ads are a necessity to keep the web free? I've always wondered what the users of adblocking software desire.
Curiously, there is a startup in the summer cycle that's working on the problem of how to make tolerable ads.