Hello all. I previously used Linux mint, but I have been tasked by my GF to share out all of our files to the 5 computers we have in our household. 3 Macs, 2 windows computers. One which I dual boot with Linux mint. My windows is only for games...don't judge me 
So I was told I should use FreeBSD/Samba to head up this task. Cool. So I am in the market for a new computer. I don't want to use any of the ones I already have as they have their own roles and i want a dedicated media server. So, I'm on the fence about whether or not I should go ahead and build one of get a premade computer. I know FreeBSD can run great on any system. I just am questionable as to the expansion capabilities on a premade. I want to setup a software raid5.
Any suggestions?

So I was told I should use FreeBSD/Samba to head up this task. Cool. So I am in the market for a new computer. I don't want to use any of the ones I already have as they have their own roles and i want a dedicated media server. So, I'm on the fence about whether or not I should go ahead and build one of get a premade computer. I know FreeBSD can run great on any system. I just am questionable as to the expansion capabilities on a premade. I want to setup a software raid5.
Any suggestions?