An Apple Mac Pro, very nice! But I do understand what you mean..
Any modern laptop will fit your needs.
If someone asked me to buy them a basic laptop I would probably look at a minimum 500GB hard drive, 4GB RAM, core i3 assuming an Intel chip, and then see what reviewers said re keyboard, display, quirks. But that's just where I'd start. With your budget you could buy a model with higher specifications than this if you wanted to. You might need a larger disk, and you might want to future proof your PC by choosing a faster processor, or more memory.
Why not look at John Lewis' range of everyday laptops to get a feel for what you like (they offer 2 year guarantees)
My Dell desktop is on its last legs, so am backing up all my docs for the day that it decides to die on me.
I don't want to spend more than £500 or £600. I have an Apple Mac Pro which DH give me as a gift and I loathe it and never use it, I definitely want good old fashioned Microsoft which is what I'm used to both in my own business (will writing) and in my dayjob.
This is what I will need it to do:
1. spend inordinate amounts of time looking at Mumsnet and fantasy house shopping
2. write lots and lots of wills (about 800 a year, average 5 pages long each) on Word, which I should probably convert to pdf for the sake of security.
5. Keep track of my accounts and a rudimentary case management system on Excel.
I don't need anything fancy, I just need to be able to park things in a sensible place and retrieve them when necessary.