Quote from Crazy Harry :

I got a P90 years ago. I payed 4.800 DM (€2.300) for it and the processor had a (well known) malfunction. I wrote several letters to Intel but they were not willing to change the CPU.

I suppose you mean the FDIV bug which is weird - I guess you missed out on their exchange program that replaced my p60 at the time.

It also had no real effect for normal use that I noticed, not even for several day-long 3d renderings and raytracing that I had used it for. It only came up if you used it to do some high level mathematical crunching - and rather specific ones.

http://www.anandtech.com/video/showdoc.aspx?i=2873&p=7

youll be just fine if its a psu that actually supplies the power it claims its able to

Quote from Crazy Harry :

I got a P90 years ago. I payed 4.800 DM (€2.300) for it and the processor had a (well known) malfunction.

My first ever laptop was a P90, had it for years and never had one single problem with the CPU. Only paid £100 for the laptop (but it did help working for the company (Compaq) at the time) The only thing that killed it in the end was the HD, Was quoted £240 plus shipping from the US for a new/albeit out of production one (and had unfortunately changed jobs). If my memory servers the HD was 170MB and it had 32 MB of RAM, and was considered the dogs b*ll*cks at the time. How times change !

I have only just joined LFS so this is a bit late.
The amount of power you are going to need depends on the system you are running eg: the number of harddrives rom optical drives fans etc. You could pay out for a 450 watt psu for £20 but pesonally I would payout for a higer watt power supply as this will give you more room for future upgrades something like 700 to 800 watt.

Quote from Barroso :

very useful for these things: http://www.extreme.outervision.com/psucalculator.jsp

I got 269 watts recommended...
Ok, i use 1 video card and only 1 HDD and 1 CD-DVD-everything-combo drive.