Does anybody have any experience with budget NAS devices?

I'm getting pissed off with shitty streaming over my home network causing HD films to stutter in high action sequences (my main storage device is my desktop PC upstairs which I use to stream films, TV and music downstairs). Wireless wasn't doing the job so I bought a couple of HomePlug devices so I could connect over my mains but it's still not good enough (possibly because my house is really old and the wiring's probably really shitty).

I'm after a NAS device that can ideally house four HDDs that runs quietly with good transfer rates. I'll then keep that downstairs as my main storage device and just shove everything on there so the TV can stream it locally via a switch.

I have a etrayz nas that houses two 2TB disks and it works like it should no problems so far.
Do you have anything in mind because a 4 disk nas is expensive.

Two HDDs should be fine. I was only considering four so I could consider RAID in the future (as I'd most likely use two drives purely for storage) but, as you've said, the price is a little high for a four drive budget NAS solution.

I looked at this one....

http://www.synology.com/us/products/DS211j/index.php

If you're building a large NAS you either want to grab those drives ASAP or wait for, erm, a year or two? The floods in Thailand are about to make the prices for HDs go through the roof cos it's where the majority of them are made and the factories have been decimated in some areas.

Synology is always a good choice a few friends of mine have a Synology-Nas and never heard them complain about it.

I use a Buffalo 1TB Linkstation with a USB drive daisychained on it. Works fine for media streaming on various devices, and has BT support.