I upgrade my motherboard roughly every 4 years so would like a little advice. I currently have the following parts that I want to upgrade:
Pentium 4 3.06GHz HT, S478 533FSB 512k cache
Epox 4PGAI motherboard, S478 533FSB AGP DDR333
1Gb (2x512mb) memory PCWorld, DDR333, DIMM
nVidia 6800 GT 256Mb Graphics card, AGP 325/1000.
Jeantech 500W PSU.
What I've picked out is:
Core2Duo E6850 3.0GHz, LGA775 1333FSB 4Mb cache
Asus Maximus Extreme motherboard, LGA775 1333FSB PIC-e 2.0 DDR3-1333
2gb (2x1Gb) memory Corsair, DDR3-1333 (CAS 9-9-9-24)
ATi HD3870 512Mb based Graphics Card, PCI-e 2.0, 775/2400
Tagan 900W ForceII PSU. (or maybe a cCoolermaster Realpower Modular1000M 100W)
so what do you think. 
NOTES
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The maximum cost is £900 roughly and the motherboard will not be upgraded for another 4 years so has to be as future proof as possible.
I have had major problems with nVidia
cards twice now and so will only get an ATi based card.
I figured that if i get the above parts I can:
Get an intel 45nm quad core CPU later as well as lower latency memory.
The PCI-e 2.0 bus should give me some options later.
The PSU should power anything that comes out in the future. Or do I only need a 750W?