We all enjoy a good comedy but if it is only one series then it has to be David Attenborough's 'life' series, starting with 'Life on Earth', followed by 'The Living Planet', 'The Trials of Life', 'Life of Birds', 'Life of Mammals', 'Planet Earth', 'The Blue Planet', 'Frozen Planet' and 'Natures Great Events'. That should keep you busy and should make excellent use of your HD tv!!
Alongside The Sopranos, The Wire is the best thing I have ever seen on the small screen as a series.
I don't watch much on tv other than sport but both those series blew me away.