As usual, Anandtech has done an incredible job with its "guides":http://http://anandtech.com/guides/ to buying PCs. I agree with most of the recommendations. Right now I'm getting a high-end system for video and photo editing and printing and another mid-range system for Calvin. Calvin's old computer is dead and that means our backup now goes to my Dad. So, time now to get a high-end ($1500) and a mid-range system (sub$1000).
Most of this is straightforward as prices and technology haven't changed much. The most confusing area this month is memory. There was a time when if you got PC3200 Ram, it was slower than PC3500, etc. all the way up to PC4400. BTW, these confusing numbers are basically 16x more than the bus speed. So, PC3200 ram means, you can run the bus at 200MHz which is stock, PC4000 means that you can boost memory speeds to 250MHz as so on. It also turns out the other way to express this is DDR speeds which are 2x the bus speed, so DDR400, PC3200 and 200MHz front-side-bus are the same numbers. Don't ask my why they do this, but its the way it works mathematically.
Second mysterious thing is that memory has a certain number of cycles between the time you give it an address and the time when you get back data. This is normally called CAS (column address select if that means anything to you). Normally CAS 2 memory is faster at a given speed (e.g., PC3200 CAS2 memory is faster than PC3200 CAS 3 memory). But, to throw you for a loop, with OCZ called Enhanced Bandwidth (see "Anandtech":http://anandtech.com/memory/showdoc.aspx?i=2019), they have a technology where CAS 2.5 memory can be faster than CAS 2. Confused now. Anyway, here's the net recommendation.
There are two things that throw you for a loop, very fast PC3200 memory can be overclocked quite a bit now, so that they are cheaper than PC4000 memory and also run faster. How about them apples. Also, the overclocking characteristics of Intel's Pentium 4 and the AMD Athlon are different, so you have to pick different memory for different processors. Here's a good summary:
h3. On the Athlon
Late breaking "news":http://anandtech.com/mb/showdoc.aspx?i=2198&p=4 is that if you have the DFI Lan Party UT Nf3 250Gb, then this advice changes, the Samsung memory performs super well with this board. Memory with Samsung chips are reviewed by Anand tech in the "fast 2-2-2 PC3200 memory":http://www.anandtech.com/memory/showdoc.aspx?i=2174 roundup.
The two tested memory products were the OCZ 3200 EL Platinum Rev 2 and the Geil 3200 Ultra X (model number GLX1GB3200DC for 1GB and GLX5123200UP for 512MB. "ExcaliberPC":GLX5123200UP has the 1x512MB memory for $160 and "BuyExtremegear":http://www.buyxtremegear.com/rm178127.html has it for$158.
The OCZ 3200 EL Platinum Rev 2 (Model OCZ400512ELPER2 for 512MB and OCZ4001024ELDCPER2-K for 2x512MB) are also hard to find. "ComputerHQ":http://www.computerhq.com/OCZ_512MB_DDR_PC_3200_OCZ400512ELPER2/products/partinfo-id-496362.html has it for $178. Newegg has the 2x512MB for "$248":OCZ4001024ELDCPER2-K. So, getting a pair is cheaper right now.
"Anand":http://anandtech.com/memory/showdoc.aspx?i=2145&p=19 recommends Ram that uses the Micron memory chips if you don't have the above board. You need to get the the Crucial "Ballistix 3200":http://anandtech.com/memory/showdoc.aspx?i=2145&p=9 or OCZ 3500EB or "3700EB":http://anandtech.com/memory/showdoc.aspx?i=2057&p=16 (275MHz max). With the Crucial, it could get to DDR514 (e.g., 262 MHz). The OCZ are CAS 2.5 memory than when overclocked are faster than the CAS 2 memory you normally would think is faster. Another oddity.
Also somewhat ironically, looks like the cheapest place to buy the Crucial Ballistix is "direct":http://www.crucial.com/store/listmodule.asp?module=DDR+PC3200&Attrib=Package&cat=RAM. Right now, its \$139 for 512MB which isn't bad at all.
h3. For Intel
Things are simple with Intel. First Intel overclocks much better and in general, if you get the new CAS 2 memory from Geil PC3200 "Ultra X":http://anandtech.com/memory/showdoc.aspx?i=2174&p=1 or the OCZ PC3200 "Platinum Rev 2":http://anandtech.com/memory/showdoc.aspx?i=2145, you'll get the most bandwidth and the ability to overclock to DDR561 or 280MHz from the stock 200MHz!
As you can see from the "graph":http://www.anandtech.com/memory/showdoc.aspx?i=2174&p=9, at DDR533 (266 MHz bus speed), the top performers were the Crucial PC3200 Ballistix, OCZ PC3500, Geil PC3200 Ultra X and Kingston Hyper-X 3200 LL with Intel hardware.