2000 would be cutting it close, especially if you are going to be using an SSD and a total of 4 monitors.
Let me start off by saying that most onboard sound on modern motherboards produce some very good sound. If you plan on doing high end audio editing though, getting a better sound card is a must as is the software required for it. This alone will send your pc build over the top cost wise as high end sound cards are not cheap.
From the sound of things you are wanting to overclock the system otherwise there isn't really a need to use water cooling. Most of the better heat sink and fan setups on the market are fully capable of cooling CPU's at stock speeds. If you want it overclocked, you should have someone build the system and then overclock it before you receive it to be sure that the system is going to be stable. Make sure that you get a warranty with the system if you do this.
As far as gaming and the CPU, I would suggest the i5 2500K CPU, but if you are going to be doing other business applications with the system such as autocad or photoshop or 3ds max I would get the i7 2600K CPU. If you are an AMD fan, then the Phenom II X6 CPU's are decent, but won't be as fast as the i5's.
Graphics, I prefer the ATI HD cards, but the nVidia are pretty nice as well. A pair of HD 6950 cards with 2Gb of ram on each would do well for what you are asking about. Keep in mind though that for triple screen there are times when the ATI in crossfire mode are not as fast due to some bug with the software. I am pretty sure they will have this straightened out pretty soon though. Triple screen setup is not possible on a single nVidia card, so using a pair of GTX580 TI cards would do good as well.
Monitors are going to be something you will have to think about. Do you want 22", 24", 27" or were you wanting to invest in some 30" or larger TV's to be used? If the monitors are full HD, they will require more horsepower to draw to than say a 22" that is just short of full HD. The larger the monitor the more you will have to spend on them. If you want a monitor with 3d capabilities, you need them with 120Hz refresh rate and they tend to be expensive.
Next question would be how much system ram are you wanting? I would go for no less than 8Gb unless you plan on sticking with a 32 bit OS in which case you won't be able to use any more than 4Gb. I would highly recommend using Windows 7 Pro as only with the Pro version or higher will you be able to download and use the XP virtual machine to run most older software properly.
