hedshotx :
Backlighting would be great. I'm in the awful habit of gaming in the dark so thats a huge plus, though I have a feeling keyboards with that feature are probably much more expensive...
Also care to explain what you mean when you say a mechanical keyboard?
I was actually responding to Hexit's post specifically, but the long and short of it is that there are basically 2 types of keyboards. The kind that comprises 95% of the marketplace is the rubber dome style. Essentially these are cheap to manufacture and fit the role of "good enough" for generic use and really for just about anything else, so long as the user realizes that the keyboard won't stand up for half a decade under moderate to heavy use (or at least, not normally). These are your Logitechs, Microsoft Sidewinders, and most anything else.
The vast minority in the marketplace are mechanical keyboards, which are referred to as such because each key has an individual, mechanical switch that is activated and deactivated on each keystroke. These are more expensive to manufacture (much more), and in turn they generally cost more (the entry price to a quality mechanical keyboard is about 100 dollars) but when a key goes bad, often times you can replace the individual switch and the keyboard returns to 100% functionality. These keyboards stand the test of time much longer, and they are also preferred by typists and some gamers. There are different switch types which provide different tactile and audible cues, and if you're old enough to remember the original IBM Model M keyboards, which were very loud and had a distinct click-clack to them, these themselves were actually mechanical keyboards (buckling spring specifically, which is more obsolete now).
Basically, rubber-dome keyboards are the product of streamlining, manufacturing cost reduction, and mass production. And really, if you have 40-50 dollars to spend, they are your only option and there are actually some that are quite fine (like the Microsoft Sidewinder X4 which has the ability to register many more simultaneous keystrokes before failing than any other rubber-dome keyboard). There are also some that cost almost as much as a quality mechanical keyboard and offer nothing more than lights or LCD screens, which don't actually provide any benefit to me nor to most people. If you want to spend more money, you can start looking at mechanical keyboards which have generally higher build quality but will come from less easily recognized brands. The Sidewinder X4 is so unique because it has very good anti-ghosting properties, allowing many keys to be depressed simultaneously with each registering (most keyboards will not accept more than 4-6 simultaneous inputs). Many mechanical keyboards further this with full nkey roll-over, meaning the entire keyboard can be simultaneously depressed with each keystroke successfully registering. The implications of this feature in gaming are relatively self-explanatory, but in my opinion anything beyond what the Sidewinder X4 provides in anti-ghosting is probably overkill. That is why I recommend it as the best budget keyboard. When it comes to mechanicals, I recommend brands like Daskeyboard, Ducky, Deck, Leopold, and Filco. I strongly advise against Razer's mechanical keyboard as it is really poorly manufactured.
Hope that covers it =). You can google Mechanical keyboards and find some really in-depth posts with actual .gifs displaying the different properties of each switch type, if it is something that interests you further. One such thread is here:
http://www.overclock.net/t/491752/mechanical-keyboard-guide