I am having difficulty using Kubuntu (or GNOME) for work because text readability is quite poor (read headache inducing) compared to Windows Vista/7 and OS X. Any tips on how to improve font rendering or, more generally, readability would be greatly appreciated! (The NVIDIA provided driver for the FX 770M gpu is installed. Also, unlikely to be a hardware issue as the machine is dual boot with Vista, which looks fine.)
This extremely subjective stuff.
But as for the facts. The code hinting patent should have just expired recently, therefore regular packages should now contain proper font hinting. Now the problem is that not all fonts support font hinting (I have no idea whether this is the case of the Ubuntu system font). Try Dejavu fonts, they do support font hinting for some time.
As for non-system fonts, try also tweaking the settings in KDE/Gnome. Both will allow you to select the style of font hinting (and font aliasing).
This link shows some old for OpenSuSe, but it contains screenshots for both KDE and Gnome, and the settings haven't really changed: http://opensuse-community.org/SubpixelHinting
As already mentioned, this is very subjective, and there are two schools of thought:
Linux gives you a choice, you can either enable full hinting to get the crisp look, or focus on font accuracy and disable hinting altogether. This can be configured either through the GNOME Appearance settings or by directly editing the fonts.conf configuration file.