I found myself using at an awful lot too - and believe that many other websites can use it too as a value add to their users by parsing parameters to it.
I found the following site that I think is excellent and just scratches the surface of what the Google Calculator can do.
I'm trying to optimize for the number 7, and also 1 through 6 and 8 and 9 too. Then I'll get 0 and every search people do using Google Calculator, I'll be #1.
It'll convert almost any form of measurement, Btyes, Currency, Distance, any unit of measure can be done. It's actually really useful and I use it all the time.
I also use google when I don't know how to spell a word... Google loads quicker than dictionary.com