I would have rated the series a perfect 10 for outstanding and consistently high quality story and character development had it not been for the last episode of Season 10!
The final episode of the 10th season "Unending", where (it would certainly appear that) the Asgard have been killed-off in a very rushed, unconvincing and very unceremonious fashion, left me in disbelief!
From the extremely rushed end of the series, it's obvious that many of the story arcs were originally scheduled to occur over at least one more season. My guess would be that they rapidly accelerated these stories to position the Stargate SG-1 franchise for the two upcoming direct-to-DVD moves!
Unless the Asgard return in a future SG-1 movie (with a very good explanation of the "apparent" extinction), I think that the fans have been cheated with a poor clean-up of loose-ends!
Poor end to an otherwise brilliant sci-fi series.