I just finished watching Season 1 of Dexter for the second time.  It's quite incredible.  The suspense is perfectly controlled leading to the finale.  It builds from the little bits of plot and story peppered in the beginning and gradually mounting an explosion in the end.

Season 2 really doesn't quite compare.  Though, it tries to do the same thing.  And has a pretty decent starting point with the aftermath of Season 1.  It does a great job of building off the previous season and builds a story of its own, which also leads to a great ending.  Unfortunately, the main focus is split.

Season 1 has a very clear focal point that everything centers on.  There are 2 main plots that eventually weave together into one.  Season 2 has a focal point, but there is too much plot.  And just a little bit of story.  Thankfully it's masked but consistant suspense.

Season 2 is still decent, but Season 1 is great.

Don't talk to me about Season 3.