In my opinion the quality of television has taken a precipitous drop in quality this decade--shows are nowhere as good as they were in the 80s or 90s--Hollywood is perfectly fine resurrecting old shows or recycling stories we've all seen a thousand times, they've substituted flashy FX and ADHD pacing for more measured storytelling that is entertaining and involving, they give us too many storylines and too many characters as plot devices rather than a modest ensemble of characters we can come to care for in a few well developed storylines.
The only shows I really have consistently enjoyed between 2000-2010:
Enterprise's uneven season 3 Xindi arc and the more consistent season 4
BSG S1 and the first half of season 2
LOST Season 1, 3, 4 and 5
Supernatural S1 and S4
Dead Zone the early seasons
Heroes S1
So LOST in my opinion is the best--it actually could be surprising, it was compelling, it was well structured from a narrative point of view, it was exciting and had new ideas to offer up. It ended poorly but it was the best of the bunch.
Other than that the rest were either mediocre, crap or pretentious bores-Smallville, Surface, Invasion, The Nine, Criminal Minds, Haven, Caprica, Eureka, CSI, L&O, The Gates, Grey's Anatomy, Private Practice, Nikita, etc etc. Then there are the shows which were birthed in earlier decades that have just become awful when once upon a time they weren't--i.e. MTV's Real World or NBC's Days of Our Lives which gave us wildly entertaining over-the-top stories such as Marlena's possession or Carly's buried alive thread turned into unwatchable garbage and should have been canned 10 years ago.
That's not even considering the non-entertainment side of things. CNN used to be a great cable news channel with solid anchors like Judy Woodruff, Bernie Shaw, Lou Waters, Natalie Allen, Aaron Brown but now we get the likes of Rick Sanchez, Anderson Cooper and poor feeble Larry King.