Agreed 2!
I buy large disks in pairs these days. One drive sits permanently inside my desktop machine, the other (identical size from same manufacturer) sits in a generic external USB2 enclosure. Backup maybe once a week (using Microsoft SyncToy), and keep the drive with you (in your car, rucksack, draw at work, whatever...).
That way you get both file redundancy and geographical redundancy. It doesn't matter if your house burnt down (well, it won't matter *that* much...) because all your important (non-replaceable) data is still safe, physically separate from the main desktop.
Like you, my data allowance is cr*p, and I don't trust online backup solutions. Do it all yourself - it's the only way to be sure.