HBO, Showtime etc. have been offering entire runs of their original series via on demand since January. I've watched a few that I never viewed during their initial runs and after viewing them I can't understand how they were so critically acclaimed. For me the Sopranos is still the best dramatic show ever - period. I thought the Wire was good but after the first season the dock workers storyline was a let down. I might give Breaking Bad another shot but just couldn't watch it the first time around. I liked the Shield - that show could have benefitted from being on a subscription network. Having worked in advertising on and off since the 80s I enjoyed the first couple of seasons of Mad Men. When the show was more about deals, drinking and dames! So much of it brought back memories - the good ol' days before anybody knew what a "Human Resources" lady was. As soon as it turned into a full time exploration of don Drapers psyche I lost interest - I got my own problems.
As far as sitcoms - I still enjoy Seinfeld occasionally and nothing beats South Park in the animation category although Robot Chicken has its moments (the James Bond episode is priceless).