Hardware solution to network several external hard drives

Hello forum members and thanks in advance for your help. I have a MacBook pro running OS 10.7.3 and I own four different external hard drives totaling 4.5 TBs of storage. I want to be able to leave those hard drives on a desk in my home office but be able to access them over my network wirelessly on my laptop. Is the best thing to do to buy a desktop or laptop to sit stationery in my home office to act as a server with the external hard drives connected by USB, or is the best thing to do to get some sort of NAS device? I'm clueless. Can I use a USB hub between the four external hard drives and whatever piece of hardware I decide to install?

I am looking for the least expensive option.

Thanks for your help, in advance. -William