upcoming xbox 720 and ps4 will likely be very nice gaming rigs --- for 300 bucks --- verses what, say 3k buck high end gamiing pc's
That's because you don't know how to buy PCs
I got my custom machine for under about 1000 € -- i upgraded it in the next 3 years with addons such as new HDD , , new sata DVD drive , replaced ram with better ones and more ram, audio card , 2x new GPUs , new mouse, new keyboard, monitor stayed the same all the time as well as motherboard, CPU , power supply and i spent like another 500€ on these updates ... which is fairly spread out on these 3 years - plus if you consider that i always sold OLD hardware to buy new so i got half or sometimes more than half of the price of the new item back from the sale of the old one

You're looking on overpriced assembled/branded OEM PCs that are on sale from HP, Dell , Alienware ... the work is what you pay for, if you assemble your PC manually by purchasing parts separately it costs you more than half less. You also need to know much skill on what to buy, reviews and forums help a lot, and for the LEVEL of hardware - you NEVER BUY the most expensive CPU, because it gives you only 10% better result , i bought Intel Q9300 (the first 45nm quads) and it cost 230 € , it's 2.5 GHZ .... the same chip that the QX version with unlocked multiplier ... so basically you spent 750 € on the unlocked multiplier which if you even know what it means, it's a term for overclocking, it means that you're not bound by the motherboard FSB frequency to overclock a processor - which is a very important thing for hardcoe overclocking - but it's totally not needed for any gaming at all (crysis:p) - practically not but overclocking is now more fun for it self todays, than it was in the old days when CPUs were the main bottleneck.
So you have to know in-depth PC hardware and how it works too to successfuly cheaply buy a PC machine that is as good as the "super workstations" DELL sells for premium - this tells you how much console people have no idea about PCs while praising their (RROD) "rigs" ... mostly 14 old kids imo.
And it's "versus"
consoles are not "very nice gaming rigs" - the current generation has had suffered from heavy hardware stability issues except Wii
You have to get a clue what high-end is ... it's not what they write on stickers and advertisments. I have a high end rig and it doesn't have the most expensive CPU , it doesn't have the most expensive GPU , that's because it doesn't need it - and it runs maybe like 20% less than the it's generation superior version.
DELL puts on their "high end machine" the most expensive models of the series or generation - it's a stupid thing for CPUs , the extra price is basically a "guarantee it's going to work on that frequency" while the CHIP has very much identical features maybe some stuff is locked off like less cache and hyperthreading in today's intel chips , but im talking about the cheapest in the sub-series, if one core or 2 cores are locked off it's already in the lower tier and the model number should indicate that.
Hyperthreading is also not that important, those extra cores are virtual and are not equivalently powerful than the physical cores so this feature is not a deal breaker if you don't have it.
THe GPUs are bit more complex because ... they can lock off more stuff and also GPUs are cards and not chips , and they rely on the card and what's on it - so lower you buy the wider is the performance drop as compared to CPUs - it's a bit trickier and you need extra and pretty much goes down to what kind of games you play and also comes all the other things since for gaming today GPUs are the main bottleneck that you need to carefully purchase.
The motherboards are different as well - but you are ALWAYS better of buying a better motherborad that has some "overclocking" features - it's not because you need that. but because the build quality is better , you don't want the main component to be cheap that makes problems for the whole PC, so you need a quality mobo for future upgrades, it's bad that you would need to replace the mobo to upgrade something that came after 6 months from the PC purchase ... stability is key and you need to have reserve - also a better mobo obviously makes PC last longer and less chance for something to break down. You might want to upgrade something or use something but you find out that your mobo doesn't support some cookie little feature ... all kinds of that little stuff that makes difference for if your PC will last long or not. And in practicse ... the better mobos don't cost that much , you just throw away money buying a 90$ mediocre mobo when a 140$ mobo is high end with all the quality. It's a small price for the benefits you get.
The next thing is also price grabbing - you need to have overview of the market - what's comming , and all local retailers you can find around or the global retailers, which one has the cheapest price, so what you do is search, you don't suppose to buy stuff from the most popular retailer - it's not always the cheapest, but im not familiar with amazon or this american stuff i never bought anything from any global retailer , i have to use local importers and private dealers. It is true that hardware is also cheaper in USA.
It's been a numer of times i grabbed the items just the right moment at the right place - all of the country had Radeon 5850 for like 150 € and i found one that sold it for 114€ and it was a Vapor-X edition

The funny thing was ... the price was increased by 25€ the next day , monday , i made my order on 23 PM sunday the previous day

That's how you buy PCs. 1500€ at most for my rig that runs everything except photoediting because i would need more RAM ... that's ~1500$ given that USA hardware is cheaper(conversion difference nulified).
STEWOX-PC7
Win7 x64 ultimate - (mid 2011) (never used vista)
CPU: Intel Q9300 2.5ghz stock - 245 € (2008)
GPU: Sapphire ATI Radeon HD5850 VaporX 512MB - 114€ (2011) [previous was HD4870( late 2008) for 240€ sold for 50€ , pre-previous was HD3870(early 2008) for 240€ sold for 100€]
PSU: Enermax 620W Liberty DXX - 150€ (2008)
APU: Asus Xonar D1 PCI - 60 € (2010) [previous was on-board realtek]
HDD: Western Digital Caviar Black 1000GB 64MB cache SATA3 (WD1002FAEX) - 95€ (2011) [previous was WD Caviar Blue 500 GB for 65 € - sold]
RAM: 6GB - Corsair Dominator 1066mhz DDR2 CL5 - 100 € for 4 GB Kit (2010 - +2 GB upgrade in 2011) [previous was Mushing 2x1GB 40€ el cheapo/unstable]
MOBO: Gigabyte P35-DS4 rev2.1 Bios-F14 - 145 € (2008)
KEY: MS SideWinder X4 - 45 € (2010) [previous was 20€ el cheapo]
MAU: MS SideWinderTM (latest, similar to X5) - 45 € (2011) [previous was 14€ el cheapo]
SND: Logitech X-540 5.1 Sorround System - 100 € (2008)
~1500€
Settings Tweaks:
- No Pagefile (HDD "virtual memory")
- No Readyboot (not readyboost) - a kind of prefetcher working at boot*
- No Superfetch
- UAC disabled
Registery Tweaks:
-optimized memory management
-Prefetcher disabled
-Full row modification
-TONS of other individual registery settings changed.
Service Tweaks:
- Homegroup Disabled
- Win Defender disabled
- Win Firewall disabled
- Win Search disabled /manual (manually operated to reduce stupidly timed index update)
- Win Update disabled (manual updates every month)