If she buys through Dell business then she will get a year's worth of on-site and remote access support as part of the package. This is extendible, for a fee. After the year, however, and the warranty had ceased, then we have out local friendly IT Crowd who will be, as you say, just a call away.
Anyone using a computer professionally should have a backup procedure in place, an external hard drive is as good as any - the odds of both your PC and the external drive failing at the same time are minute. Of course, I wouldn't keep the two together in case of theft, or heaven forbid, fire.
A grand buys you a LOT of technology, you could easily get a high end machine, with 8GB of RAM and a couple of those super duper hard drives UltraSBM has been talking about. In fact it would be face meltingly quick.
If a custom built solution is required then emphasis on large amounts of RAM and fast hard drive - be it RAID or SSD.
Can you RAID SSD drives?
