I'd, in turn, recommend reading books besides those suggested by one RPG writer you happen to like. The Gies books are not the "bible" of Medieval Times. I own nearly all of them and I have to say they're quite good introductory books, but relying on any single source can be dangerous. Try going to the library and reading through the books there to get a more diverse viewpoint.
Social classes in the Middle Ages were not as strictly defined as we'd imagine. As commerce grew, merchants emerged as wealthy and influential figures often eating and drinking better than priests or knights. Please refer to "The Middle Ages" by Morris Bishop or "The Year 1000: What Life Was Like at the Turn of the Millennium" by Robert Lacey for a description of the wretched state of many priests and knights that I referred to.
In fact, there were many poor priests and knights (whether by choice or not). While many people may imagine Medieval Europe as a place where princesses in flowing robes awaited their knights in shining armor, it was a much grittier world than that.
For example, Dominican Friars were forbidden to own property, so they often had to beg for food.
http://online.esjc.cc.al.us/scovingt/westciv/unit3-2.htm
"... there were many other orders of clerics who lived like parasites on society: wandering friars, for example, who lived off what they could steal from honest folk."
http://www.saradouglass.com/14th.html
Most of the knights who went off to the Crusades were poor knights. There was an "overpopulation" of knights, especially in Normandy. So, the journey to the Holy Land also provided an outlet for these restless souls many of whom were impoverished and indebted after the various wars (1066 invasion, etc) and ongoing changes in the economic system.
Not all priests and knights were poor, however. Indeed, many were in privileged positions of power and prosperity. However, they did not "evoke great reverance and awe" nor did they "wield enormous power and influence in almost all levels of society" as the starter of this thread stated. Certainly, the mere appearance of any priest or knight on the streets did not "cause massive crowds to form and gather for a glimpse or a touch".
By the way, land ownership is not necessarily a prerequisite for knighthood. Often people were knighted on the battlefield for heroic acts (or being among the few to have survived) without consideration of whether they owned land or not.
One thing I do have to point out is that my comment was focused on priests. However, knights were also not as glamorous as we often conceive either as pointed out. I may have also exaggerated when I said "most of them wore rags", etc. Most did not, but many did.