I think there are certain things only you can decide, and PC or Mac is one of those choices lol! Wherever you ask you'll get a 50/50 split about what's 'best' and ultimately what's best is the one that you're happiest with. I'd say go with the Mac if you're not comfortable with PCs.
I think the most important factor here is that you create a space you feel comfortable with, and one that you don't feel you need to keep adding to.
Is there a budget now and then a budget when you sell your gear?
Yeah I've read the pc/mac arguments on here! I'm certainly a pc user and have no hatred there but I sit in front of a pc all day at work too so a change would be nice.
My budget may go up but it is based upon the rough trade-in price of my gear, I already sold a novation d-station, a-station, akai dps-12i, MPC2000XL, but this old gear aint worth much these days! Still got the prophecy, nanopiano, nanobass, soundcraft 16 track desk and some other fx etc but not counting on raising much cash. I could never afford the expensive gear when I was younger, I'm in a better position now, but want to make sure I buy the right stuff to do the job, and not compromise on quality (like I had to in the past).