Large storage options

A while back I bought a NAS for storing digital pictures pictures and iTunes library (lots of movies). Never been happy with the NAS and now I think it's having issues. Lightroom is struggling with the pictures (finding file errors that never existed before) and copying files from the NAS to my iMac is also having issues.

Not sure I want to spend money on another NAS, but not sure what other options I have? I could buy a large hard drive and put it in a Thunderbird enclosure (if I can find one). That would work for LR but iTunes stores everything in one folder and I'm concerned about running out of space.

With my D7100 large files sizes, photo storage is going to be an issue...eventually.

What do folks here use or recommend?

Thanks

Can i ask 1 question, and that is how much do you want to spend ??

If you have a few $ i would suggest you go Drobo.
Im getting a 6K tax return in about 9 days and I'm putting in a order for the 5N but wouldn't mind having the 5D with the Thunderbolt and USB3 connections. Ill make that decision then lol, but Drobo are of quality and reliability

EDIT : Im going to go for the new Drobo Mini With the quickness of SSD's it will be a beast hahaha

That looks spectacular but also out of my price range since it appears to come empty.

Let me ask a different way...is there a RAID storage solution that is NOT a network drive?