You can add google cal events from quicksilver – and it gets better. If your first search matches an address book contact and then hit a text-entry switch (. or '), the contact’s full name is entered for you!
Like others, I find that quicksilver is so well designed and so absolutely essential to my using a mac that I forget that it isn’t part of the OS. It is a thousand times more useful than any dashboard widget ever could be, and its visual feedback is as stunning as exposé.
It is also the fastest and easiest flickr uploader.