This is a Little calculator with no little GUI buttons.
First thing most noticable is that there are no little gui buttons. Everything is reachable from the keyboard, so I see no reason to build a bunch of buttons that just get in the way.
It has a stack for memory storage, and is used in completing operations. Even though there is a stack, The Calculator is not Postfix notation. All operations are still infix. This might seem a little odd, but I find it works quite well. You have the stack for doing some really deep stuff, but its all still infix which just seems more natural. (my opinion anyhows.)
It supports labeling decimal numbers using most of the SI standard labels. (The exception is deka- for which the official label is da, but I use D instead. By doing this all the labels are a single character.) Decimal and floating point numbers can be labeled, just type the label character in last. Hex, Oct, and Bin numbers cannot be labeled. The ‘best’ label for a number can also be calculated.