Please give me some NAS advice.

You state that you want to use the device to "download torrents." I assume that you mean you want to use the device as a destination for your torrents, not to actually perform the downloading. Most NAS devices won't offer the ability to run applications on them. If you truly want to handle both the storage and the downloading you will want to build a system that has a fully functional OS. However, there are definitely some advantages to getting a NAS. Management is easier, there are fewer things to go wrong, and setup will be much quicker. I have used a buffalo terra station for quite some time. It has proven reliable, fast, and secure. Buffalo has a few products out there at a great price.

aldoenviro, if you'd taken a look at the link he provided you would've seen that he's talking about a NAS with BT client installed. So no, it's absolutely not necessary to build a system for that. I have a QNAP 209 NAS which can handle downloading of usenet, eDonkey and BitTorrent files. And besides that it runs a web server, FTP server and is an UPnP media server for media clients like the PS3 and XBox 360.
A NAS is much smaller and consumes less power than a full blown system.
The model I have contains 2 HDs in RAID 1 mode so if 1 of them crashes I can hot-swap it for a new one without losing any data. But if you don't need that you could also consider buying the TS-109 II

QNAP 109 II

QNAP 209 II

Wow, my mistake! I didn't even know such an appliance exited. I spend my time mostly in the enterprise sector. I should take a look at more of this SOHO equipment.

Although such a device may have network attached storage, I think it falls outside the definition of a NAS. I would consider this more of a media center or some sort of dataset management appliance. Regardless of the definition it seems like a great addition to any home network or a media heavy SOHO network.

I own a ReadyNAS DUO (2x500 RAIDX) and I love it... it handles torrents good (not perfect, but there's an update in the works)... it streams UPnP great (my xbox has a new family function) and once you start filling it up you'll look to upgrade your HD size quickly... I've owned mine for 6 months, never down, no failures, frequent updates to both firmware and supporting software, and I will be purchasing two 1.5 TB drives in the near future (newly supported)

Visit ReadyNAS for a great community and loads more information.

~*Out of the Box Ready*~

Just spent the last day setting up my first nas. Great learning experience. I used an old mini itx machine I had. VIA processor 800mhz, 512 ram, and 120gb hd (I need another hd though). I used freenas. After a little prep reading, it was a breeze and works well. I use it to centralize my data, and to stream to my nintendo wii. Flawless. I initially wanted to buy a ready made nas box, but at around 200 just for the enclosure, I'm glad I didn't. Freenas has alot of options, upnp, webserve, bittorrent, ftp, ect and because I had the parts lying around.....free! So if have spare parts, build one. There are other os's you could use i'm sure, and you don't have the parts, I'm sure you could pick up a dinasaur of a computer for around $50.