The mark of a good keyboard - like a good butler - is that you shouldn't notice its presence. It may be the main intermediary between PC and user, but generally it's only when something goes awry that a keyboard gets noticed - often right before being thrown across the room.
Logitech has a good history of producing keyboards that aid, rather than hinder, frustration-free interaction with one's computer. I used a G15 for several years before finally upgrading to a Microsoft SideWinder X6, after it suffered an untimely death at the hands of a cup of coffee. I still regard the G15 as one of the finest keyboards I've ever used and the G110 follows in its footsteps admirably.
The design is unsurprisingly reminiscent of the G19, sans both the LCD display and the utterly ludicrous price. Logitech is asking £69.99 for the G110, a more reasonable proposition that the G19's £150-odd MSRP, even if not exactly cheap.
The G110 packs its fair share of features. There's a USB port on the back, but more interesting are the microphone and headphone inputs. The G110 includes built-in USB audio processing, letting you hook up a set of headphones and a microphone (or a combined headset, of course) without the need for a soundcard.
I'm not entirely convinced this is a particularly worthwhile addition. The quality seemed as good as the Realtek chip on my motherboard, but that comparison betrays the flaw: most PCs already have audio processing. It's only potential benefits are in bypassing integrated audio that's of particularly poor quality, but this is an increasingly rare problem these days. Unless you have a specific need for it, then it's hard to justify the cost.
Of greater use are the G110's built-in macro and multimedia keys. On the far upper right sit play/pause, stop, forwards and back buttons, with a mute button and a volume wheel placed beneath them. Leftwards from this is a toggle for the keyboard's backlight so you can turn it off when you're watching a movie, for example, and farther left are separate mute buttons for attached headphones and microphones.
Even more left-wise there's a switch for disabling the Windows and right-click menu buttons, so as to avoid frustrating minimising of games. Finally, to the left of the main keyboard, are macro keys (G-keys) above which sit the three M-keys that enable you to switch between different macro key profiles.