Well, there's a long list of good products out there. It will be easier to write down what to avoid and watch out for.
- Don't buy PC Chips or ECS motherboards. They're the cheapest of the cheap, use the crappy Chinese capacitors that always blow, and they're really flaky. Plus they usually crun on crappy VIA chipsets. Pretty much all the others are good, but most of the time you'll see recommendations for Gigabyte, ASUS, and Intel motherboards.
- Don't bother with cheap power supplies. Yes, you can get a 500 watt power supply for $12 if you get a "CompUtek" or whatever, but it's going to be a crappy one with a lot of noise on the line. Remember, every other component in your computer relies on the power supply, so get a good one. (Corsair, ThermalTake, and Cooler Master are good ones.)
- Get a decent hard drive. Maxtor has improved its product lineup a bit, but I still prefer Western Digital and Samsung drives. There's no excuse, especially now that you can get a 1 TB hard drive for $75 (even no rebates).
- AM3 and Intel's i5/i7 CPUs only support DDR3 RAM (to my knowledge), which is much more expensive than DDR2. going with a brand new socket will give you more opportunity for upgrades don the road, but will be more expensive in the short term compared to a similarly-speced AM2+/LGA775 setup.
- More cores = more things done simultaneously. If you plan on doing a lot of multitasking, or if the games you want to play can take advantage of it, look into a quad-core. However, if most of your games only do 1 or 2 cores, they'll run better on a dual-core with a faster clock speed.
- Load up on RAM. For everyday desktop use on XP, 1 gig is plenty. On Vista/Win7, get at least 2 gigs. I have 4 gigs right now and it cruises through everything.
![Cool 8)](./images/smilies/icon_cool.gif)
RAM is the cheapest and most effective upgrade you can make to a computer (well, to a point anyway).
Now, what's your budget?
EDIT: Here's an Intel i5/DDR3/Nvidia setup which is more or less equivelant to the PC I built. It will tear through pretty much everything out there right now. (Remember, the i5 lineup is a minor update / rebadge of the Core 2 line, however it uses the new processor socket so it's a little more future-proof) The CPU is equivelant to a Q9400:
Here's basically the exact setup I have (but I reused the optical drive and hard drives from the PC it replaced, and a ghetto-arse ATX/BabyAT case from the mid 90s). It scoots along really well, but pretty much represents the end of the line for LGA775:
Same as the above build but with an E8500 dual core instead (NewEgg doesn't have any dual-core i5s listed yet):
One based off that dual-core Athlon II you posted:
(Might not be the cream of the crop because I'm not partial to AMD/ATI and don't follow them as much)
Same as above but with a Phenom II:
I don't generally include cases in the builds I post
(mainly because I think most of the cases out there look like crap XD), and I'll give you 2 price totals: 1 with everything, and 1 without the video card so you can see what the rest of the parts cost and add your own. (I bought the GTX 260 216 and have been pleased with it, and the HD 4870 is pretty much its equivelant.)
None of these were picked with multiple video cards in mind. If that's something you want, then you need either a higher-end motherboard or one based off an Nvidia chipset to do Crossfire or SLI (respectively).