Best Weather, Calculator and Unit Conversion App

Ok people there has been a lot going on with this types of utility apps so I thought we could decide in general terms which app is the best in each category taking into consideration things like features, UI, functionality, etc.

Personally I'm looking for one in each category because it doesn't look like Tapbots would be updating either Calcbot or Convertbot for the iPhone 5 screen and the default weather app is plain boring for me.

So let's go and thanks!