[ArtWilliams]

My question is, can I set it up so I can access it from a Mac and a Windows machine?

Yes, you can. I have my home networked with Linux and M$ machines. One advantage is that you can have large files stored on one machine including backups and multi-media (i.e. movies). My favourite is being able to share a good printer.

Are there any advantages, disadvantages on having a server setup?

None, other than taking the effort to put it all in place.

Also what linux distribution is better for this?

I use Ubuntu for my desktop but I would recommend Fedora for a server. I would guess that more servers have Fedora on them then any other distro.

I need all the help I can get, and I need specific answers since I have a general idea of how I would like it to work. Does any of this make any sense? Any ideas, suggestions and opinions are welcome.

I hate to say this but if you're technically challenged and you just want simple file sharing and maybe want to share a printer then install Windows on the machine and turn on Printer/File Sharing after running the Home Network wizard.