Yes, I always work while batch rendering. In some fields you can sit and render, but not construction. My bosses would have a fit, despite me having two Piledrivers at the office for working double-time. Even when both are rendering, they want me busy - or else they’d just get me a third computer, making life even more unwieldy. Two is enough for me, speed-wise.
In Windows, you’re gonna want a process management utility to help out. Task Manager isn’t really enough. I use ProcessLasso, which gives you tons of options and tools and most importantly, lets you easily set your Default Affinity and Priority, and gives you an additional thread for “Responsiveness”. Incidentally, this program alone closed the rendering gap between Win7 and Win8, which was initially 10-20% depending on your CPU. So Win8 is slightly more optimized at the per-thread level, but it was easily corrected here.
Here’s an example, on my 'Dozer at home:

So you set a couple cores OFF for “MayaBatch.exe” and that’s it. It may bog down momentarily on a few things, such as dynamics calcs or texture-loading, but generally it’s at least 95% as responsive once you turn off the first core or so for rendering. On the Piledrivers, since they’re two logical cores, I turn off two. You can probably get away with just one on the i7.
Yeah thats one thing I love about gpu renders like redshift. Its using gpu, so my computer is completely free to keep working.
@Refract: How well does that work if you’re using Viewport 2 and a decent-sized scene, though? 