I've found the Google Search Service a very nifty and useful part of life when using OS X, as well as the great coca apps that are out there (like iJournal!). In fact, I've found that it's most useful when typing up an entry, deciding that you need to find a link for it, and using Google to come up with a good link.
I'm aware that you can change the default key for the service, but for those of us that are lazy and creatures of habit...