If you're going to buy a new Intel processor and put together a system that you plan to keep for a few years, I recommend going with an Intel 975X north bridge chipset such as that found on the very nice ASUS P5WD2-E motherboard. However to do this you need to get a CPU with at least 800Mhz FSB. You will also be able to use faster DDR2 800Mhz RAM if you do this.

If you really want to go with the cheaper 533Mhz FSB CPU, an Intel 945G chipset would work and still provide room to expand later. A good motherboard with this chipset is ASUS P5LD2-VM.

Personally I prefer AMD CPUs and nVidia chipsets. An Athlon 64 X2 performs well and will work great with future 64 bit operating systems. The motherboard I'd recommend there is the ASUS A8N32-SLI Deluxe (nVidia nForce SPP 100 / SLI chipsets).

In case you didn't notice, I like ASUS high end boards. But you can get other good boards with the same chipsets cheaper. You'll be giving up some special overclocking features, onboard RAID, 8 channel audio, dual gigabit ethernet... and other stuff you might not need. If you buy a cheap one make sure you'll be able to return it if you have problems.

As for memory: Once you pick out the CPU and motherboard, buy the highest rated memory that your motherboard supports (for example with an A8N32-SLI you should buy "DDR 400 (PC3200)" RAM or with a P5LD2-VM you should buy "DDR2 667 (PC2-5300)". If you are into overclocking you should learn more about RAM timing, etc. Otherwise just buy a good brand of RAM with a rating that matches your motherboard.

As for RAM brands, Crucial makes very good quality RAM. Mushkin, Corsair, Kingston are also fine. For a high end system, I wouldn't buy other brands than those.

If you're doing gaming you will want a nice PCI Express x16 video card. I'm rather partial to cards that use nVidia chipsets (many available from companies like Gainward, Chaintech, XFX etc.) but also the high end ATI cards are nice. If you want a hardcore gaming machine, buy the nicest video card you can afford, OR, save money with a cheaper high performance card based on nVidia 7300/7600 and you can upgrade later. (And before you buy an ATI "All in wonder" card ask yourself if you really are going to watch TV on your computer, and if not, don't.)

It really comes down to what you want to spend and how long you can wait.

Personally, I recommend waiting until the Intel Conroe CPUs come out in the fall. The current Pentium Ds run really, really hot and suck up a lot of power.

I'm currently running a Pentium 4 2.8. I run IIS, Vis Studio 2005 and SQL Developer as well as multiple browsers simultaneously just fine. I'm switching over to AMD as soon as the Asus AM2 micro-ATX motherboards come out next month.

You can spend alot $1000-$1400 or a little under $600. It just really depends which way you want to go.

About 3 years ago, I went small and quiet with a bunch of external drives.

Case - Buy a good case because it will be the last thing you switch out. If you go mid-tower then go with one of Lian-Li PC-V1200 models or the Antec P160. I use a micro-ATX minitower. I don't like the one I have now so I'm going to buy a new case the CoolerMaster Centurion 451 for my new system.

PowerSupply - Zalman or Seasonic . One of these brands. They're powersupplies are as close to silent as you will get. You'll need at least 400W if you're running the current Pentium D.

CPU - Wait for the Conroe chips. Seriously. Wait till fall.

Motherboard - I've started using Asus about 6 years ago. I'm never using another brand again. What your looking for is 4 DDR2 RAM slots, 3.0G/s SATA and PCI-Express slot for your video card. This will leave you with an upgrade path for your video card, RAM and CPU.

RAM - I've been using Mushkin for about 8 years. But I'll be switching to OCZ. OCZ makes great RAM with really fast CAS timing. You're looking for a timing of 3-3-3-8 or better. DDR2 533 because that's the speed your CPU is running at unless you plan to overclock which I wouldn't recommend consider how damn hot the Pentium Ds run.

CPU Heatsink - Zalman because they're very quiet

Video Card - GeForce 9800 if you can afford it. Otherwise GeForce 9600. I don't do much gaming so I use ATI for video. You'll need a PCI-Express card

Sound Card - SoundBlaster Audigy for gaming is what everyone I know who game uses. I'm still trying to find the great card for audio. Haven't really found it yet.

Speakers - I love my Klipsch speakers

LCD Monitor - Samsung (if you do graphic design) , otherwise Dells LCDs are good at half the price and I don't think you'll have any ghosting issues since they have a 12ms response time. 8ms is better but you'll end up paying alot more.

DVD-RW - I use LG drives. I think the Plextors are the best but I like the LGs because they're very fast, reliable and quiet..

Hard Drive - Samsung SpinPoint or the Hitachi 250G because their fast and quiet and 250G is the current sweet spot for price ($85). I currently run a Seagate 250G but it's louder than I thought it would be. All my externals are Seagates and will continue to be since I've never had one go bad. I use the Venus DS3 Serial ATA to USB external enclosures to house my hard drives.