It seems that aesthetics have a great deal to do even with PPC text-based ads. Shoemoney has an interesting tip that he has used to improve his click through rate by 25%. He explains

Notice how the bold words form a arrow like > ? That is a nice eye tracking trick that for me increased clicks by about 25% in ANY SPOT. Discovering this for me was a HUGE THING because more clicks means a higher quality score which moves you up for more exposure which means you get more clicks which… well you get the point.

If you're not sure what Shoemoney meant, I'm not a Doctor offered this picture (to the right) to better illustrate it. Essentially, even though text-based ads aren't flashy, looks still count.

Via SEOptimise.