What is with you people!?
Why are some of you so compelled to flex and posture about overclocking, and alienate would-be overclockers?
If you take your 805 and your p5nd2 and get some good ddr2-800 memory, install a decent aftermarket fan/heatsink, and put some Arctic Silver 5 on it according to the instructions, you should have no problem getting 3.5-3.6ghz on stock voltage. Shoot, if you lap your processor and heatsink and do it correctly (something I have not much seen discussed on these forums), you can probably easily hit 3.8ghz on air.
Perhaps if you are not going to overclock you should not buy an 805, but for the less than $200 USD you will pay for the motherboard and processor, you're getting a dual core, 64-bit processor and a motherboard that supports SLI, albeit not true dual 16x SLI.
And what do people mean by overclock? Just because you plan to overclock does not mean you have to break 4ghz for it to be a successful overclock. I wish people would qualify some of these open-ended imperatives that they issue, like "oh, if you're gonna overclock with the big dogs, you can't just emulate the THG article, or you're gonna get took out the game, son!"
And what is the rationale behind the notion that if you are going to overclock, you have to water cool??
Some basic stuff:
1) Get a good power supply. Look on Newegg for a solid 500-600 watt power supply, though 500 watts should be PLENTY. I personally have had good experiences with Thermaltake power supplies, but if I was in your shoes I would look for an inexpensive 500 watt power supply that has a lot of customer reviews of 4 or more stars/eggs.
2) Get a good motherboard. The Asus P5ND2-SLI that yourmotherisanastronaut recommended is a good choice because it has 8-phase power regulation (something I have so far only seen of Asus boards), and it can be had for under $100USD.
3) Get a good heatsink/fan combo and good thermal paste (you can't go wrong with Arctic Silver 5). You don't need watercooling to get a great overclock, and in ways, you are preserving more of the essence of what makes the 805 D overclock so attractive by not watercooling - namely, price-performance ratio, and ease of implementation (and when time is viewed as money, time saved becomes money saved, which further enhances the price-performance ratio.)
As for heatsink/fan combos a lot of people like the Zalman CNPS9500, but there are other good ones. Look for a 2 or "dual" ball bearing fan design.
If you want to take a little extra time and get the most out of your system, do a Google search for: lapping heatsink cpu
In a nutshell, lapping your heatsink (and your CPU, in the case of processors without an exposed CPU die - such as P4 or Athlon 64 chips)
consists of sanding the surface of your heatsink until it has a mirror finish - in other words, until you can clearly see your reflection in it. I have done this half-as*ed, and I have done this properly; when done properly, it has dropped my CPU temp by 40 degrees fahrenheit! Forty degrees!!!! Your results may vary. Anyway, look for a guide on the web or PM me if you want to learn more about it.
4) Get memory that can support your target clock. DDR2-800 of any stable variety should fit the bill in this case. If you really have your eye on performance, shell out a little extra for lower-latency memory.
5) Good airflow through your case. Whether you take a standard case and intelligently cool it or buy a case that looks like it has a turbine in the side of it is up to you. A good side fan and good rear case fan should do the trick, but make sure your cables are placed in such a way as to allow for the most airflow possible.
Good luck with you new rig, lavery.
-Rambuswolf/khennsu/bok_bok