First and foremost.... do NOT rely on any disk system to be a one-stop solution for live storage & backup. Having a good backup strategy with multiple copies is so important.
Personally I think Drobo are expensive and would rather throw the money at an empty QNAP NAS chassis and populate it with my own drives. I use QNAP NAS devices in work and they're very good. You do need a decent amount of computer literacy though to set them up (though that could be said of any NAS/networking system).
I understand what you mean and this what i am looking at so i have 3 copy's of my images! So i am looking into different way to do this! So far i got external hard drives, but i what to do bit more so i can have of site as well! Cloud not a option as i got very slow broadband!
I will be looking at NAS but what putting me off a bit as there running 24/7 and i not what the noise! How noise are the QNAPS units please?
Unfortunately I couldn't tell you how noisy they are as there's a rack of full-sized servers in the same room (and they're very loud).
If the QNAP cases are anything like my Netgear one... you can tolerate them for working, but you will notice the hum from them if (say) you have them in an adjacent room to where you sleep (unless either you, or the case itself powers down for the evening of course).
Many NAS drives can act as DLNA media servers nowadays (mine work happily streaming uncompressed music and H264 video to my AV amplifier). The bigger ones from Synology and QNAP even have HDMI ports and subsequent video/audio decoding hardware built-in (as well as a remote control) to plug them straight into TVs/monitors but with the added bonus of having multiple drive bays for plenty of expansion.
The main drawback for a NAS is that you're limited by what you can execute on them (eg. antivirus) but providing you're using a decent sheep-dip methodology then you shouldn't have issues.