The keyboard itself sports a very simplistic design compared to some keyboards we've reviewed here. Although it does have a few extra function keys around the num pad and off to the left, there isn't a whole pile of them across the top as we're used to seeing. Instead, the top of the keyboard has a very stylistic arc which holds a screen with two buttons under it to switch between screen modes. The screen has five modes; time, media, temperature, hot-keys display, key counter and inbox update. Now for a quick description of each mode:
Time: This mode displays the date across the top with a large digital clock in the middle of the screen.
Media: This mode shows the name of your current song as well as a track bar with the current location in the song.
Temperature: This displays the room's ambient temperature via a built-in thermometer in the keyboard
Hot-keys: The functions of each A, B, C and D hotkeys are listed on the screen
Key Counter: Counts keystrokes (rather self-explanitory).
Inbox: Shows the latest emails in your inbox

(Click below to enlarge)
  

The other separate function keys that we usually see across the top of a keyboard are on the F keys on the MX5500 keyboard (note the great design of these F keys in the pictures below!). In place of what would usually be the right side windows key on the keyboard, Logitech has placed an Fn function key like we're used to seeing on laptops. When you press this key along with any F key it will then do the second function as indicated in orange on all the F keys.

Media playback buttons are located in two spots on the keyboard. Up the left side you have your typical media controls and under the num pad there's a media center button along with photo gallery and gadgets buttons. Also over with the media controls on the left side is a zoom button and Flip 3D button for Vista (in XP the Flip 3D button is replaced by Logitech's application flipper window).

The calculator button above the num pad does not open the windows calculator like most calculator buttons do. It actually opens a calculator that is built right into the keyboard and displayed on the keyboard's display (how cool is that?). While we're in the num pad area I should also mention that it's just a number pad here. There is no num lock because there are no secondary functions to these keys; they're just numbers. Personally, this is something I really like because I've never used a num pad for anything more than just it's numbers in all my life. So by keeping it just numbers, there is no num lock to worry about and the keys are kept very clean looking with only one function needing to be printed on them. I'm sure everyone will see this differently though depending on how you personally used this pad.

Although most good wireless keyboards these days can achieve a year or more in battery life on 2 AA style batteries, the MX5500 can only average around 185 days on 4 AA batteries. With having to run the LCD screen on this keyboard, the batteries unfortunately must work harder than in traditional wireless keyboards thus leading to faster drain times. So as to not leave you stranded, the Logitech Set Point software will show you the remaining days for the battery life in both the keyboard and mouse. Of course the day counter is just a rough estimation, my keyboard stayed at 184 days for around a week.

The key layout was just like any standard keyboard, no ergonomic arcs, separations or wave designs to the keys; just a flat, straight key pad. Although I must admit that the MX5500 looks like a sleek sports car, I really wish that it would be more ergonomic for the money I'm paying for it. If Logitech were to take this keyboard and keep it exactly how it is but add an ergonomic key pad and maybe stretch the wrist rest out another centimeter or so, it would probably make it one of my favourite keyboards.