Here is a great video illustrating excerpts from DFW's commencement speech at Kenyon College in 2005. I post it here because I fully agree with it.
To entice those who won't watch it without some sense of what to expect, I'll tritely summarize (but I really think you should just watch it and read the full speech). The speech addresses the same issues Wallace was writing about in his unfinished novel, The Pale King. It starts with the notion that we all live life in the default mode of our own egocentric perspective. This, however, leads to a life of banality and meaninglessness, which we try to fill through worship of something--anything--whether spiritual, material or superficial. The only freedom from this banality comes from arresting the default egocentricity through radical awareness of the moment, which leads one to become aware of the experience of others. The best quote from the speech is:
The really important kind of freedom involves attention and awareness and discipline, and being able truly to care about other people and to sacrifice for them over and over in myriad petty, unsexy ways every day.
Such a loss that he left us so early. I wish I understood why the shackling weight of his own depression became no longer bearable.
The full commencement speech has also been made into a brief book called This Is Water: Some Thoughts, Delivered on a Significant Occasion, about Living a Compassionate Life. The entire speech is also available for free on the web.