Having finished the book, I can now feel comfortable in strongly recommending David Foster Wallace's book to everyone. It's a challenge to read - it took me over two months to get through it, trying to read for at least half an hour a day; and it's not the sort of think you can half-focus on, while you're tired, or have had a couple of drinks. It demands full engagement.
Some might also be daunted by the bleakness of many of its topics: depression, substance abuse, loneliness. But the characters are so vivid and alive, and the style of writing is so entertaining - every sentence shoots off in four or five different directions, and the dialogue is killer - that the reader is usually too busy enjoying the style and the plot developments to get emotionally dragged down by the subject matter (except for during particularly poignant scenes, which are more than made up for by numerous hilarious ones).
Only upon finishing the book does the emotional heft of the story fully hit: all those characters, clinically depressed, suffering from addictions to alcohol, pot (aka Bob Hope), cocaine (aka Bing), or a remarkably broad spectrum of other substances, or recovering but dealing with daily urges, or simply feeling alone and at loose ends. But it's not all negative; some of the characters manage to gather themselves together and muddle on, and are incredibly inspiring. Knowing that Wallace himself was ultimately unable to do so is a real kick in the teeth, though.