Now that Convertbot 1.4 is out, I'm permanently switching from Convert to Convertbot. Its UI is kickass! Sound effects, calculator mode, plethora of units, oh my!!
I was just at the post office picking up a certified letter when the Postal Person next to me asked if anyone could convert 200 grams to ounces. I tried to do it in my head, then watched as they struggled together to figure something out.
I whipped out my handy iPhone, opened Convertbot, and asked how much they needed to convert and voila, i had the answer! They thanked me and went ahead with the transaction. Great app!