The other thing that the internet can help you with is deciding your spec. I can't find it now but mr Google found me a site where I told it what I needed the pc for, (multiple choice q.s) and it then told me the spec I needed.
On portables, having worked in a couple of Cos where cost did not seem to matter when it came to pcs, (!!!) I allowed the techies to buy me bells and whistles pcs. In my last Co, I just went for lowest possible weight due to weekly commuting. Didn't miss any bell or whistle.
PS
It might have been this.....
What Computer Should I Buy?