[amitash]

1.I wouldnt worry about the hardware remaining in working condition...It will live for a long long long time, provided you dont overvolt it.

2.IMHO:

PSU: you probably wont need to change this untill it dies mainly because hardware nowadays requires lesser and lesser power to run...I would say a good psu will easily last atleast 4+ years

mobo: The intel x58 chipsets and the lga1366 socket both support the new intel procys coming mid next year which are the westmeres (6cores 12 threads) so i dont think you will need to upgrade the mobo for atleast untill the next archaetecture of intel procys aka sandy bridge comes out sometime late in 2011 (this is the predicted time)

procy: The 8 threads of the core i7 are a very formidable force indeed and since no game or program fully utilizes this raw power you can expect to see the performance increase considerably in the coming 2 years...IMO if you buy nehalem now, its best to skip the westmeres as i think it will last all the way till sandy bridge comes out.

HDD: whn you run out of space obviously.

RAM: this too will last a really long time as ddr3 isnt utilized perfectly yet...It should last along with ur procy till the next arch comes out.