Windows Calculator can switch into a "Scientific" mode, getting more math and logical operators, but that's not good enough. I know there are tons of features its missing, such as the ones we see in the Windows 7 calc, or simply making things more visual. Its been years and I still haven't found a good calculator replacement.

Suggestions? And hopefully your calc replaces MS Calc when I press the dedicated "calculator key" on my Keyboard, so I don't have to hunt around for a shortcut.