Backing up is a serious matter. It is very possible you have more money invested in what is on your computer than in the computer itself. My music collection far exceeds the value of the computer on which it is stored. There is also the reality that some things we now store can simply not be replaced. Consider the value you place on your pictures. I am thinking now is the time to look around for inexpensive backup options. There seem to be many sales on external and internal hard drives of all sizes.
Here is a recommendation I think you are likely to overlook. I like the BlacX from Thermaltake. I admit it looks a little weird, but I will explain my support for this product.
The BlacX allows the insertion of internal SATA drives – the type of drive you install in your computer rather than attach outside. The drives pop in and out of the base like cartridges. Internal drives are significantly less expensive than external drives because they draw their power from the computer and have a less expensive enclosure. You can often purchase these drives in the 250-500 Gig range for $60 or so. So, buy one powered unit (the BlacX) and several internal drives.
Leo Laporte (podcaster) convinced me that you may be better off with multiple smaller drives rather than a single large drive (after I had already purchased a terabyte drive). It is cool to have the largest drive, pickup, or whatever, but the advantage may only be bragging rights. Leo suggested you backup the hard drive twice (perhaps in alternate months) and store one drive off site (home to office and office to home). The idea is that this strategy protects against catastrophe. Purchase multiple drives somewhat larger than the capacity of the machine you want to backup.
BTW – look around for prices on the BlacX as well.