This all sounds very fun! But hey I'm a huge geek
I've accomplished all of that but using the DIR-615.
Black spots are a huge pain in the a*se, like you said just run a cable to another Access point (AP) that will cover the black spot. You could look at powerline adapters if you didn't want to run cables here there and everywhere. I'll link a few at the bottom. They run your network through, effectively, you home power cables. It's rather awesome!
If you were to run a cable or powerline to a new AP. I would recommend doing this next to your PS3 and then using a port on the new AP for your PS3 connection.
NAS is very easy to setup, Synology are very reliable and easy to use. I think thats your best bet, just hook it up to your main router and config the settings and your off.
Before you go buying anything, check out the Slingboxes, I'll link it below. Excellent TV streaming system!
Powerline // http://www.amazon.co.uk/TP-Link-PA411KIT-AV500-Powerline-Adapter/dp/B0084Y9N3O/ref=sr_1_1?ie=UTF8&qid=1366543918&sr=8-1&keywords=powerline+adaptors+triple
Slingbox // http://uk.slingbox.com/
So here is what I am trying to accomplish.
Right now I only have a DIR-655, a have computer, my PS3 and a printer connected to it wirelessly.
Only using the DIR-655 creates a few dead zones in my house. I thought about placing another router/access point and bringing a network cable from the 655 to this new device in my living room, that way I would be able to eliminate the dead zones and connect my PS3 to network using wires instead of the wireless.
I am also planning of adding a NAS to my network for backup and streaming, I had a look online and the Synology 213 so far is my pick and I also might add a WD live hub so I can stream it's content (.mkv) to multiple devices.
From my researches I found that a DAP-1522 would be a good choice, however another DIR-655 would be the exactly same price! So, which one should I go for? Other alternatives are always valid as well! I just never had problems with D-Link!
If you guys have any other idea or tips, please let me know! This is what I am trying to accomplish:
*Eliminate the dead zone
*Connect my PS3 to the network using wire
*Add a NAS (Synology 213 probably) to the network for backup
*Add a device so I can stream form my NAS (Maybe a WD Tv live hub)