The Windows 7 calculator first looks real good and has a few more functions, unfortunatly they've gone and crippled it if you're a computer programmer like me or need to swap between decimal and hex regularly.

In the old Windows Vista/XP calculator in Scientific mode you can swap into and back of Hex+Decimal. The Windows 7 calculator now in "programmer" mode to have hexadecimal, you can still swap between decimal and hex but the decimal no longer allows a decimal point! This makes everyday calculations impossible, plus if you forget your in programmer mode and go typing in a number with a decimal point without realising your calculation will come out wrong.