For the money, you'll definitely get more (hardware specswise) with a PC than a laptop and it's very easy to switch out parts on a PC. I haven't partitioned my PC, but do make monthly backups of my OS drive, and do highly recommend in doing this. It'll save you the headache/time of re-installig everything from scratch (if something does happen to go south with your DAW).
If you're comfortable doing your own build, that's a fantastic way get each & every component that suits your needs and you'll have control of what goes on in your machine..........generally, buying PC's off the shelf will get you a inferior/cheapest components and you'll get a lot of bloatware preinstalled. I personally think that building your own PC is the best way to do things on a tight budget.......I built mine and I'm just an amateur/hobbyist.....so anyone can do this.
If you prefer to have someone build it for you, then I'd contact the two Pro builders in here: Scott at ADK or Jim Roesebrry at Studiocat........they're both in the States, but are the DAW guru's in here.
My drive confiugaration is:
C: OS/all software (250 GB SSD)
D: Sonar projects (1 TB HDD)
E: Synth Samples (3TB HDD)
If you're not going to be using a lot of soft synths that usually require big sample libraries, then you may not need a 3rd HD, but possibly someone with more expertise might chime in on having 1 HDD for Sonar projects and samples.
Once you decide which way to go, you can always post the projected specs for your DAW as there's a lot of knowledgeable/helpful people in here willing to help you with your build.