Not entirely true...Physicists love macs cuz they're unix based.
Basically use the best tool for the job within the confines of the budget.
I just got a new Lenovo for work. Good computer. Regularly crashes at the moment running Office though. So I could recommend it as it's a good machine, but can't always recommend MS's coding. Can be fine. Can be an inescapable nightmare. Your mileage may vary.
I'm happy with my 1.5 year old 17" macbook pro. It's my everything computer so i like how it does everything it's supposed to without lots of tinkering, or me having to disable stuff that I might want when I'm not doing music production. If it's a dedicated music machine then you can probably save a few quid with a PC. But I still couldn't use the trackpad to swipe back and forth between Live and other software, or do 2-finger scrolling around live in all directions. (Yes, you can enable some of that functionality on this Lenovo - not Expose or Spaces though, but I can't fathom how it's possible to make it SO inferior to Apple and so turned it off and use a mouse else it just annoys me).
Basically, if I'm gonna buy a £2k laptop I'll wait til the newest macbook is out and buy that when it's best value for money. If I had a cheaper dedicated machine, or wanted to spend less then I might well consider a PC but would do a lot of research on it first.