$2000? Challenge accepted

CPU - Wait until June for Haswell, Intel's latest line of processors

Motherboard - Also dependent on Haswell launch, but you should be able to get one by May

RAM - You said you want a lot, but believe me, RAM changes so dramatically in price so quickly that you should just get 8GB now (more than enough) and wait until you actually have a reason for more. I made the mistake of maxing out on RAM with my first rig (16GB) and ended up wasting a lot of money. I actually dropped down from 16 to 8 because the particular kit of 8 could be overclocked MUCH higher and is still more than I'll ever need until at least the next version of Windows. I would recommend you the same kit I have, but I'm not sure where to find it.
A good alternative would be this G. Skill kit

Graphics - The Radeon HD 7950 is pretty much the best bang for your buck out there. $300 may seem a little steep, but it'll still be kicking in a few years. I highly recommend this model from Gigabyte since it comes slightly overclocked, but most have been known to clock even higher by a large margin. The cooler is about as good as it gets for air, and it's supposed to be very quiet too. If you want even more performance you could get up to 4 of them, but of course that would be expensive.

Storage - As mentioned by many others SSD's are the bomb. Even better they're much cheaper now days, and you can sometimes get 256GB drives for under $200. I myself have been using a 256GB OCZ Vertex 4 for about 9 months and it's wonderful. I would recommend either an OCZ Vector or Samsung 840 Pro. If you need more storage just grab a 1TB+ HDD from Western Digital. Not Seagate.

Case - Regardless of whether or not you need the space, a full tower case is always a great idea unless you absolutely need the system to be small. A case is something that can easily last for 5 years or more, and retain a lot of its value. The best full tower out there that doesn't break the bank is the NZXT Switch 810. It's barely a year old, has tons of room, and is easy to work with. It has plenty of room for liquid cooling, if you ever get into it. This is another component I myself own and I love it. Right now I've got in it 2 stock cooled graphics cards and a liquid cooling loop with a massive 120 x 360mm radiator in the top. At $170, it's an excellent deal.

Power Supply - This is where you can't afford to screw up. If you cheap out on anything never make it your power supply. The worst part is that most PSU brands are more so bad than good, so you have to be very careful. Corsair and SeaSonic are both very good, but I recommend SeaSonic since they make their PSU's themselves and charge the same or less than Corsair. Buying a PSU that supports way more output than what you need is a bad idea due to the inefficiency it causes, but you still need to leave room for upgrades and possible degradation of your PSU. This Seasonic 850W should serve you well.

Cooling - Also dependent on Haswell release, since it will be on a new socket that few or no current coolers may support.

That's about it for now, and your total is 80 for the RAM, plus 240 or 250 for an SSD, 300 for the graphics card, 170 for the case, and 120 for the PSU.

$910 or 920 (Missing CPU and Mobo, but those shouldn't run you any more than $500 together)

I can make changes as needed due to budget, personal preference, etc.