Advice for a new Computer

My first desktop computer was a Tulip visionline :Pentium 90 Mhz with 8 Mb of Ram
Of course,the memory prouved insufficient and was augmented to 16 mb which was a HUGE improuvement
Tipically,when you buy a new computer ,you basically buy the best and most expensive processor with a lot of garbage added
At that time ,the newest processors were Pentiums at 90,100,120,150 Mhz
I challenge you to find ANY diff btwn the 90 and the 150 Mhz version ,although the latest was for "professionals who can afford to pay 5 times more":))))
BUT,If you take that old proc and add 512 mb of memory ,you can still run Vista totday,although very,excruciatingly slow
Typicaly ,people do the next mistakes:
-they spend a huge ammount of money on a new computer
-then they realize that they need more memory,a video card, asound card ,a wireless keyboard ,etc
-so they spend another huge pile of money
-then they realize that they need a new computer

So my advice is:
-buy the cheapest proc from the best line
-do not buy experimental models like "quad-core with 2 dual-cores inside"
-do not buy very new models ,as each line of processors yields good and bad processors and at the beginning they are all sold at 1000$ each;later they are placed into categories:e2140 for the worst,e6550 for the best dual-core
-do not buy celerons with deactivated cores-60% perf reduction
-buy the cheapest video card for your mb from the newest line of videocards:same comments about quality apply here
-buy the cheapest motherboard from the newest line of chipsets(x38);do not buy expensive third-party chipsets from Nvidia,Ati,VIA,etc
-buy the best power source with 80% eff
(3 times I changed my computer because of a faulty power source which shuted down it at times)
-buy the best 7.1 surround system,monitors,mices,keyboards and other peripherals
-buy the best web-cams ,hdds from Creative ,Genius or WD or Seagate
-do not buy peripherals from producers like Manta,etc