EDIT: Made a couple changes suggested by posters in this thread. Changed my PSU and added an SSD. This did add about $150 in cost.
Note: At the $2000 price point, I am reusing my Windows license, existing hard drive and optical drives only. Everything else is new.
As with any build, this is all a matter of opinion, budget and hardware preferences. The only thing that really matters is that you build a machine that works within your constraints.
I just finished doing the research and speccing out my new build. My builds go for bang for the buck performance. I don't case mod, or light everything up with LEDs to show off. My computer sits at home in my home office and It is the center of my technology universe, which obviously includes gaming.
This build is *absolutely overkill* for MMO gaming, but I build my machines to be very poweful across the gaming spectrum for a minimum of 3 years without the need for a single upgrade. My last machine was a first gen i7 920 cpu with a GTX 295 (dual gpu card) that was strong up until very recently, and then happened to die on me.
So here is the core build, with some explanation after:
Comments: There is a lot I can say here, but I will try to scale it down. The new 3rd Generation Intel Ivy Bridge i7 3770K fits my needs well, as I do some video editing where raw throughput is helpful, as well as some other multithreaded computing applications. With i7 I get 8 cpu threads. I considered the 2nd Gen six-core i7 (12 threads), but it really wasn't worth another $250, especially knowing that I would rarely spool up all 12 threads. Keep in mind that most games are still only using one or two cores, so for gaming, anything more than a quad core is a waste anyway at this current time. There are other benefits to the Ivy Bridge cpus out now, such as lower power consumption, and native USB 3.0.
Having said all of that, if you don't *need* the additional throughput of the i7 CPUs, look at the i5 2500K. It's a very popular quad core that happily overclocks and doesn't expell as much heat as the 3770K. Don't buy a six core unless you have money to burn, or you need the additional threads. 99% of people simply don't need six cores, and you don't need them for gaming. There currently are no Ivy Bridge six core CPUs in production.
Comments: I love ASUS. I almost waited for the new ROG Maximus V Formula board coming out soon, but the boards are very similar, and I need a machine now. The P8Z77 line has been lauded across the board by reviewers, so you can't go wrong. It will do all kinds of overclocking and has most of the latest ASUS features. If you were planning to do extreme overclocking I would say wait for the Formula, or get the EVGA FTW board. If you want a great deal, get the Pro instead of the Deluxe and you still get most of the features.
Comments: This great RAM costs about $100 for 16GB. It's a good deal. It is CAS 11 RAM which could be better, but more importantly it is pc2133 speed. Cas 9 RAM will cost you another $100, and you won't really notice the difference. If you are going to do extreme overclocking, look at G.Skill instead.
GRAPHICS:
Comments: DO NOT waste your money on a GTX 680. Benchmarks show that the 670 is just slightly slower, and I mean slight. As you can see, I am putting in two 670's which puts me just under the same performance as a dual GPU 690, but for $200 cheaper. Guru3d.com has done extensive bechmarking of the whole line, as have other reviewers, and concludes by telling you to buy 670s unless you want to piss money away.
A single GTX 670 is more than enough for most, if not all, MMO games out now, or releasing in the near future. The only exception to this may be if you want to run max resolution and graphics settings on a large 27"/30"screen, or run multiple screens. Then you will benefit from Sli the most.
SLi rocks. My last build was a GTX 295 (dual GPU) that was strong for over three years right up until it died last week. I was running both GW2 and TSW with all settings maxed with no problem on a three year old SLi setup. Spend the money on a good multi GPU setup, and you will be good to go for years. Start with one now, add another later (when they are cheaper).
Comments: This case owns. It's a little more expensive at about $150, but it's cheaper than a lot of other full tower cases with less cooling capability. Worth every penny.
CHANGED: POWER SUPPLY:
Comments: I originally had what turned out to be s sub-par power supply (Thermaltake Black Widow), but thanks to some posters here, I picked up the above unit instead.
ADDED: SSD:
OCZ Vertex 4 VTX4-25SAT3-128G 2.5" 128GB SATA III SSD
Comments: I wasn't going to do an SSD, but the posters here convinced me to give it a shot. I'm not convinced that I want to use this for Windows yet, but I will test it out. The size is small, but will work for the apps I am most interested in boosting (such as Guild Wars 2 and The Secret World). TweakTown gives this SSD a 94% rating as of May 2012.
Conclusion
I consider this, for my use, to be the best build I can do for about $2000. It uses new Ivy Bridge tech (Z77), and gives me room to upgrade and/or overclock if I want later. The 3770k CPU gives me all the CPU power I need for gaming, plus the extra threads for other things I do such as video encoding, graphical work and folding@home.
There are several things that could be scaled down to save money:
You can get a good mid-tower case for well under $100. A good motherboard can be had for $150, rather than almost $300, and you could cut out one of the 670's until later when they only cost $200 or so. If you aren't really going to overclock, you don't need the liquid cooler. There are killer air coolers available for $35. In otherwords, you could still build a screaming single GPU system for a little over $1000. As people have noted you can build a great mid-grade MMO gaming rig for even less with a less expensive graphics card.
On overclocking: For pure gaming, get the i5 2500K quad core. You don't need an i7, and you don't need Ivy Bridge. Sandy is still preferred by a lot of people. Your motherboard and RAM are important here too. Read reviews.
I'll post some pictures once it is put together this week.