1GB is 1GB of RAM. It doesn't seem to have onboard ROM, but SD slot surely will support up to 32GB. And it has 10/100 Ethernet besides USB, though latter is probably suitable enough to "connect a lot of disk space".
USB2.0 will push 480Mb/sec which is probably sufficient for streaming content.
My wireless router has 64MB of ram and is capable of running as a NAS device if you plug a USB enclosure into it.