I agree that the vast majority of tv is useless at best and even harmful in some cases, but there are some gems, though few and far between. The only shows I watch regularly are The Daily Show and Colbert Report, they both do a great job of blending irreverant humor with current events, and alot of times they're saying very relevant stuff that wouldn't fly unless it were under the guise of comedy.
Discovery's Planet Earth was awesome btw. Survivorman's good too.
Les Stroud is cool as **** in my book. The monlogue in the last minute and a half here might be the coolest thing I've ever heard on tv.