Worst decision of the whole meal. I find myself breaking out in a cold sweat, gripped with indecision, thinking, "The last place I went had really terrible, salty soup, and it ruined everything!". So I lean toward the salad and think, "But the salads are usually nothing more than the limp, wilted bitter pieces of lettuce with a couple of rock hard croutons and a watery, bland vinegar & oil dressing!". Then I usually end up saying "Neither." and eat the bread.
But I suppose if I HAD to choose, I'd go salad over soup 80% of the time.