Do you actually have a home rack mount and decent home connection, or are you looking at colocation?
If you're looking at setting it up colo you're probably better off just renting a Minecraft server - it'll be infinitely cheaper. If you've got space for it at home and a connection that will actually be good for hosting, your best solution would probably be to build one yourself (Newegg stocks server hardware)
But here's a good alternate idea if you're hosting from home: try using a laptop.
I've got a laptop here with an i5 and 6GB of RAM. It's plenty powerful enough for hosting a Minecraft server (my connection is just terrible). Get one with an Ethernet port, sit it cabled direct to your router.
As a bonus, since a laptop has an internal battery, that acts as a UPS. If your power goes out, there won't be any data loss and you can go and safely shut the laptop down if the outage lasts a while. You also don't need to set up RCON for the server unless you're going to be administrating it from out of home - you can just head out, open the laptop up and access it directly.
You can also claim you own your own hardware! People love that stuff.
