What's all the parts needed to build a gaming desktop/laptop?

Motherboard

CPU

RAM

Graphics Card

Hard Drive

DVD drive

Decent power supply - not the crappy ones you get bundled with cases

Computer Case

Optional:

Sound card (most motherboards today have perfectly good sound capabilities).

Monitor and peripherals are down to your tastes, but bear in mind that very high resolution monitors require beefy graphics cards to get the best from them.

I think Intel's Core2Duo CPUs offer the best bang-for-buck right now, as do Nvidia 8000 series graphics cards. The 8800 GTS 640mb is the best performer-to-price card out there (the GTX is faster but more expensive) but it might be a bit too pricey still. If you can afford it, that's the card to get.

Build A Gaming Laptop

Listing specific parts often comes down to personal opinion and how much money you are willing to spend. I recently purchased two Lenova PCs and two MSI NX8600GT-T2D256E OC GeForce 8600GT 256MB 128-bit GDDR3 PCI Express x16 SLI Supported Video Cards for playing WoW and performance is very good at a reasonable price. I get 60fps while using the highest settings (occasional dips in fps for intense scenes, but still quite good).

Cost: $499 for PC + ~$110 for video card

If you really want to build a great system, check out the 8800 GTS card and look at one of the higher end motherboards, a faster processor and RAM. You could also play with the disk configuration to ensure the page file is on a separate controller and use faster disk. As long as money isn't the limit, you can build a nice system.

All the parts needed to build your gaming desktop would be the following things which I've included links to some of the best rated ones for each part that you will need.

Processor - http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

RAM - http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Motherboard - http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Graphics Card - http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Hard Drives: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Case - http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

These are the main things you'll need. Since computer parts gets better all the time, instead of recommending you specific ones, just look on those pages for the best rated ones. It's always updated so it doesn't matter if you read this 5 years from now, you'll still see the best up-to-date stuff.

Other specific recommendations would be a sound card, fan, power supply, keyboard, mouse, DVD drive, and a monitor.

Since you want to buy parts for a gaming desktop just for gaming like playing World of Warcraft, those things should do it. Now laptops are a bit harder to get customized and upgraded so if you're going to build one, a desktop would be easier.

If you want to get a laptop instead, I suggest saving yourself the trouble and just buying one that meets the requirements for gaming.

motherboard

processor

graphics card

hard drive

power supply

case

the optional:

wifi card

sound card

monitor

Others have mentioned the main components so here are some of the best parts to buy. Amazon updates these lists regularly so no need to worry about outdated parts:

Best Motherboards: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Best CPU/Processors: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Best Ram: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Best Graphics Cards: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Best Hard Drives: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

Best Cases: http://www.amazon.com/s/ref=sr_nr_p_72_0?rh=n%3A17...

The rest of the stuff such as power supply, keyboard, mouse, fan, etc., you don't need to worry as much of brand/quality since they're pretty standard.

From what I've seen, Amazon has some of the best prices and most items come with free shipping so I'd buy these things from them.

Well Michael C. I had a power supply included with my case and it worked flawlessly for 21/2 years. In fact I took it out still working and opted for one with more watts.

And if you want good parts, go to tiger.

for playing world of warcraft your computer is going to need a heavy graphics card and also depending from where you play a LAN accelarator

also check out this site they specialize in gaming computers

If you have never built a computer before I would recommend you start reading up on technology. It would be easy to say what all components are in a computer, but to say what parts are best for your scenario isn't a simple task.

I will say this, at the cost of building a system, you will invest easily 2 to 3 thousand dollars for anything up to speed with the latest technology at an entry level.