[Build Help]Home Server Build

Ok, where to start?

I am going to graduate college soon and want to spend a portion of my first check on a home server. I've done a bunch of research, but am unsure about a few things. Feel free to be technical. My main interests are streaming media from it, and lots of storage space

OS: I have heard that Windows Home server does a ton of stuff for you, including streaming to remote devices. I have access to windows server 2008 for free. Does this come with all the things Home server does? I have also looked at linux distros for this. So far, I haven't been successful in finding media management and streaming services that are straightforward and good. I don't mind tinkering, but why would I if I don't have to (feel free to suggest programs if you know of any)?

RAID: I hope to use a raid 5 or 10 setup. Should I do software RAID or buy one of those expensive RAID cards that have 8 ports? Are there any other cheaper alternatives so that I can have many (more than 3) hard drives in reliable RAID? If software RAID is a good option, what do I need to be able to do RAID 5(OS/software wise)?

I've also looked at pre-built boxes like Drobo. They seem really neet, but I thought it would be nice to be able to run other services on this box if I wanted to (which as far I can tell you can't on Drobo because they run a non-standard OS). By other services, I might run a minecraft or meebo server on it.

Also, other tips on home server builds will be appreciated. A bit of background, I've built a server before with a pretty standard mobo with 4 sata ports. Windows 7 offered software raid 1 or 0 so I chose 0 like a fool. So I'm looking for something more official.