Anywhere else on the internet, you'd have come dangerously close to starting a holy war. Me, I'm a Mac guy, and I hate those Windows guys with the passion of a thousand blue screens of... wait, sorry, never mind.
The fact is, just about anything... anything... that you buy today will be perfectly fine for music. If your question had been "what do I need for video production?" we'd be having a different discussion. But get something in your budget, and that you're comfortable with. Prioritize more memory (RAM, I mean) over any other kind of upgrade.
Well... maybe anything except like a Chromebook. But any Mac or Windows computer, just get what you like.