Didn't want to hijack Guy's Desktop thread but I have 30+ years of history in buying the wrong computer - our first, the Sharp MZ80k cost £800 back in 1979 or 80

Followed that with a Spectrum and eventually an Amstrad which also cost £800 some 9 years later. Three years on and we got our first proper PC with windows at a cost of, you guessed it, £800...
I have an unhappy knack of buying just at the point when the technology is about to make a big shift and render my purchase outdated faster than it should be. So now,
New laptop in the planning stage and looking for advice
I don't want a bog standard HP/Acer/Whatever because it's going to be the main pc for the house and we'll use it with a usb keyboard and a proper monitor most of the time but with the added flexibility of a laptop
What will it be used for?
Wife's general work stuff using Word/Xcel etc
Email
Internet browsing and all the usual stuff
Grandson's low level games (he's

My big project of turning old family videos and photos into something more interesting - most of the videos are already in digital form, as are the photos but my previous attempts at creating a proper edited movie have foundered due to a lack of processing power in the existing machine.
I know I should be able to do something with the standard WIndows MovieMaker but in the past, even when I got something edited and ready the DVD burn failed
It won't be used for much else really - my laptop handles my other interests and the iPad is so much easier and more convenient for things that the pc used to be essential for.
What am I looking for in terms of appropriate processor and graphics?
Where do I look and how much should I be spending?