When I started looking at parts in May 05, I had everything ordered and knew what to do within a few weeks of becoming interested in building my own machine. It took me 2 or 3 days since I started before I got my 6800 GT and... another part, can't remember, Ram or HD. a necessary item. Finished up the day I got the final parts.
Putting it together is the easy part, it's all pretty much straight forward. The hardest part I found was learning how to order the parts, you had ddr 400, 184 pin etc, everything had to match up.
Final answer, 2 days max for you. Likely a 1 day job.
Newbie since 2005.