How much money do I need to aquire a Desktop WIndows 7 PC capable of playing Crysis 3 at maximum settings, because if it can play Crysis 3, it can play Battlefield 3, Far Cry 3, The Witcher 2, Arma 3, and possibly games that uses Unreal Engine 4.
(I am planning on getting my own desktop for next year)
Well, for starters I am going to take a different path here from what the majority is suggesting since you have indicated you don't want to build a computer. So long as you are aware and I am guessing you are at this point, that you will pay a substantial premium for a quality turnkey solution that is fine. It's your choice, your time, your preference and your money. I think you should do whatever you damn well please personally. It's good people have pointed out the options but you should not feel compelled to build a computer just because all the cool kids do it for example. They are right actually. It really is not very difficult generally speaking but at the end of the day, it is your computer not theirs and your money and time, not theirs. So do what you please is my suggestion here.
That said, Alienware is a popular choice for a quality gaming rig that just works out of the box and comes with a comprehensive warranty which you probably can and may want to extend if the price is something you feel is reasonable for the peace of mind. I would expect to pay somewhere around $2,000. or more, maybe even $2,500 for an Alienware that meets your requirements. You can look them over for yourself and custom configure them for yourself and see what price totals come to at their website.
Unfortunately, as was pointed out earlier longevity in terms of running the latest, greatest games at maximal settings is going to be limited to a relatively small number of years no matter what you buy. You could buy a triple SLI Falcon Northwest machine with water cooling and everything else for 10 grand but it will still not play the newest games at highest settings in a few years. It's not like buying a console which for its entire life will play games at their best for the system. PC gaming performance invariably degrades slowly over time as pertains to playing the latest greatest at max settings.
If you always want to play PC games at max settings all of the time, you are in for an expensive ride in the coming years is what I am getting at.
Lastly, here is something important that I think you need to keep in mind when purchasing a computer next year. While buying the best rig you can afford (within reason) is generally a good idea for what future proofing you can get, which again is always going to be limited, big changes are coming to PC games when the new consoles hit which could be as soon as about a year from now.
When the new consoles come, this is going to up the ante substantially in the graphics department and possibly the processing department too. At this point, many triple A titles are ported to PC from the consoles where the big money is for game developers. We can reasonably expect these next gen games to be considerably more demanding for max settings folks in particular on PCs. So what I am getting at in going on about all of this is that no matter what you buy next year, it is going to take a hit performance wise when next gen consoles and the leading gaming titles which will be ported to PC arrive.
Why is that information especially important now? Well in my opinion it means sure, get a nice machine but do not go overboard spending a high premium for "the best one" at say a place like Alienware where you'll pay dearly for it. Because in just a couple of years or less it is not hard to predict that you will need to spend even more money upgrading the thing, particularly the GPU(s) in order to continue being able play everything at max.
Anyway, if you have the money then knock yourself out. It's expensive to be able to do PC gaming at max all of the time but it can be done. It's just expensive as hell.
The only other thing I'd add which occurs to me now is that in my opinion, max settings are greatly overrated. A lot of times the difference between max and high would be hard to perceive if you were tested with two systems and did not know which machine was running what, most especially if you were not told you were being tested. I wonder how often people would even be aware there was a difference in just sitting down to play since high settings on modern games look quite good in many cases. In fact, medium settings can look pretty decent on modern games. And then there is running high settings but turning down resolution which ultimately produces a pleasing display that requires pushing a lot less pixels.
I am someone who has never bought the top end. I do not consider the relatively minor gains to be worth the premium cost for them. With gaming requirements soon to ramp up quite a bit I'd say, next year is not really an ideal time to buy a top end gaming rig unless you are saving a lot of money perhaps by building one. Unless money is not an issue here for you. If that's true then well, enjoy your Cadillac of computers. I respect your right to do whatever you like there. It's your PC. :D
I hope all that rambling was somehow helpful.