As a serious gamer, the only one I would ever buy is the Wii U. Despite the fact is less powerful than the others and will almost certainly receive the least support from all third party publishers, it will still receive the Nintendo games, which are are worth of the price of buying a console for. As for the XBone, it will eventually have very few exclusives worth of playing and, while the ps4 will have some, I would argue you will do much better with a PC instead of buying a console from either Sony or Microsoft.
Sony is making a point the ps4 is just a hyper charged PC. Well, it is actually a very capable PC for the money they are asking. However, if you're willing to expend the double in hardware, you can assemble a PC more powerful than the ps4 that will be fully compatible with previous generations of games (and thus have a rich library unlike the ps4), and much much cheaper in the long run as Steam's discounts are much better than anything Sony can ever try.
I wouldn't get too hung up on Exclusives. In the grand scheme of things, they're more of a "grass is greener" kind of thing where you find the other console has something you can't have. I certainly wouldn't put much stock in XbOne not having as many exclusives. Given that in the current gen MS stole how many exclusives from PS3 (like FF), Exclusives are an artificially inflated "feature." Plus, there will likely be an even distribution of exclusives, as there always is.
Now your argument for PC games is interesting. Aside from my complaint that PC games are seldom tech-support-less (meaning % chance of me not getting called to straighten out a problem is higher than zero). Cost is a big factor to most gamers.
$400-500 gets you a console that will be stable and supported for SIX years, based on the Sony declarations and market observation. Any game that comes out during that timeframe will work on your launch day machine (assuming your launch day machine lasts, as the prior generations did). And you will NEVER have to spend time configuring drivers and such to get your game to work.
When people suggest to BUILD a PC for $1000, how good is that PC for gaming? How long will that PC last before it starts to be sluggish on the newer games. You'll probably get 2-3 years, before you need to start upgrading parts. Newer video card, more RAM, faster hard-drive. New motherboard to support faster CPUs.
We're not even talking hardware reliability, assuming all physical parts suffer no problem for the time you own the gaming machine, you will likely need to upgrade the hardware to keep up with the newer games that were written to expect better hardware at their release time.
Every console gamer should admit, that the PC version of the game is always better. Better frames per second, rendering distances, ability to be modded, etc.
Every PC gamer should admit that the better game play comes at the price of more expensive equipment and more labor to maintain it.
Most console gamers accept that their PC is just for surfing the web and doing term papers, and that the console provides a trouble-fee escape from doing term papers and technical complexity.
As such, buying a cheap $500 PC to surf and work and a $500 console to play games on the big screen TV is a better investment than a $1000+ PC to play games on a monitor (most people don't hook their only PC to the big screen TV as you can't do WORK that way).
There's plenty of people hooking a PC to their big screen TV and playing games. But they're still the minority in cases I've observed. Whereas, dedicated appliances getting hooked to PCs like xboxes, iTV, Roku, etc aren't even blinked at as unusual.