I just watched season 1 of Rome and have started season 2. Season 1 was really good. The show portrays as charming and intelligent those characters with ambitions to dictatorial power. Those concerned with the concentration of power in the executive are whiny bitches. These are politically suspect decisions in the time of the Bush administration, but it's all good fun.
Plus, there's a ludicrous but rousing adventure tale of two Roman soldiers who happen to have an accidental hand in the major events at the death of the Republic. Not at all stupid and Forrest Gumpy, rather they're charming and Dr. Whoey.
And then the second season, or at least the first 3 episodes, turn incredibly bleak and depressing. Julius Caesar's dead, so the bulk of the delightful scheming for power falls to Octavian, who up and left the show (I suspect that he'll be back).
Season 1's Cleopatra had rolled about on her couch, smoking opium and getting laid left and right. Now she just complains about her kid.
And those two soldiers? Let's not get into it. It's a real bummer. I hope that it gets better as the season wears on, but so far the thing lacks the verve that made the first season so much fun.