Problem with using laptops for recording is always noise. Laptops get hot (cos there isn't much space inside them) so have fairly ferocious fans.
Solid state drives etc alleviate this problem somewhat, but they are much more expensive.
There are a few things you need to consider before deciding which laptop:
- Input/Output connections. What audio interface are you going to be using the laptop with? Are you going to recording ensembles, do you need to hookup to much external hardware (like a mixer, effects, preamps etc)? Will your audio interface need USB 2.0, USB 3.0, Firewire or even ethernet? Thats a big question as just deciding how many e.g. USB connections are needed will limit your choices, or require that you buy an external, powered USB hub (consider that you might need to connect an audio interface (or more than one), dongles for software (an iLok for example), probably a mouse (I couldn't negotiate a DAW with a touchpad) and probably even an external drive (for storing all those space consuming wav files).
- Are you going to be using it primarily to record music such as acoustic guitar, vocals etc, or do you like to make music 'in the box' using VST instruments etc.
Will you want to use plenty of plugins or be mainly using it like a tape recorder?
This will effect what kind of speed and RAM requirements are needed.
You'll also probably want a fairly large screen as DAW's have a hell of a lot of visual information to look at.
Finally, I'm presuming that the reason you want to use a laptop for recording is because you need it portable (you are recording all over the place). If not, I'd seriously consider a desktop as a better & more flexible solution.
If you need to do location recording, I'd also consider a dedicated hardware recorder that you can take around with you and a desktop installation at home, where you would transfer tracks for final mixing etc.
