I want to build a desktop computer and i was curious to what advice people can offer to me for this project?

Things like the mother board and what website i should buy from. I was wanting to build a decent system that runs XP. So i was just wanting any advice anyone can offer for meI want to build a desktop computer and i was curious to what advice people can offer to me for this project?
for the motherboard will be Asus.....and the Video Card will be Nvidia Geforce AGP Video Card and the RAM will be 1GB or if not try 512MB....then put Pentium 4 with 3.40GHz and for ad-ons will have a Card Reader, 2 USB Ports, dial-up socket and LAN socket Infrared and Bluetooth built-in and mic and webcam built-in....and last the OS has to be Windows XP Media Center Edition Service Pack 2.....how about that? i hope this works for you.....gud luck on your project...^_^I want to build a desktop computer and i was curious to what advice people can offer to me for this project?
make sure you dont spend more than you need to depending on what you are going to be using the computer for. www.newegg.com is a good website and has reviews from customers.
if this is your first time building your own system ..GO SLOW , first decide which based system your going to use AMD or INTEL , then do some research on the motherboards [consider what youll be doing with your computer now and in the future] Motherboards are the heart of your system , Next thing to consider is how much money you want to spend ? thats the biggest question right there.... custom built machines can really expensive , after you figure out the money part and the system , make sure you check out compatability with each component you want to buy , id do alot of google searches for advice first .. Its easy to get in way over your budget if you just jump into it [trust me on this ] try OVERCLOCK.NET sign up for that and join the discussions , theres alot of good people there with alot of great advice .... good luck