Some of my single tracks can exceed 40GB!
But then again, that's 6+ individuals recorded separately before mixing
Any song you find that's greater than SACD/DVD-A size (meaning, an individual song on either format), is 99.999% to be a pointless waste of space. Why? Because it's pretty much the OPPOSITE of an mp3 file; people take the original, and "add" stuff that wasn't ever there, at any point, in the original recording. I challenge you to find me any popular album released as a 48bit/192Khz audio format, and I already win because it is too inefficient.
Regarding hard drives....
While I think that a good SSD (Samsung 830 256GB is STILL my absolute favorite, and IMHO the best made so far... 840Pro, Plextor M5P-Xtreme, and the like are also excellent) makes some things far faster than anything short of enough hard drives to fill the NSA's daily spying quotient all in one big RAID0 could meet
However, that is not to say that I don't think RAID0 has its benefits, in fact for someone who works with media (recording... which are large...long....SEQUENTIAL writes, and when played back they are large....long....SEQUENTIAL reads), a good RAID0 is hugely beneficial!
But, RAID0 is far more costly than many people think. It is not "$ of HDD x2", but rather "$ of RAID HDD x2(or more) x2+1" because unless you have a solid mirror in RAID5 or better, that RAID0 data may as well not exist. I know I'd lose a LOT of money if that happened to me.
Personally, I would consider "best practice" for people working out of their homes in a similar fashion to myself to be:
SSD 256-512GB for OS/Programs
2x 1-2TB HDD for Work
1x 2-3TB HDD for in-case Backups (done immediately)
NAS/DAS with 4-12x 1-3TB HDD's in 1-2x RAID5/RAID6 arrays or a couple RAID10 arrays, connected via eSATA or better (if you can find one that allows access to one array via eSATA and another via USB3.0, well, let me know too!)
Oh, and you should keep ANYTHING truly critical in a 2-bay 3.5" enclosure that has 2 drives in it, either "JBOD" or RAID1 depending on the amount of data, and the external enclosure kept in a safety deposit box.
That's how you keep data safe. Don't trust "the cloud", because it's very easy for private data to become public, although for other things having a redundant online storage system is useful and quick. Multiple copies, in multiple locations, is really the only thing to ensure you have adequate time to rebuild the redundancies...