Crimespree's Jon Jordan posted his thoughts after watching Seasons 1 through 5 of Smallville on DVD, which led me to ponder my own experience of the series.
Season 1 of Smallville was one of the first DVD sets I bought. Very impressive introduction to the relationships and good foreshadowing to Clark's future.
Looking back, seasons 2 and 3 had less momentum, which is why I think Lois was introduced in Season 4. Lois Lane engages Clark Kent like no one else, a nice change from his close-mouthed staring and pining for Lana.
As uneven as I've found the series, I still watch each week. The production values are great, and there's always the chance the writers will riff on classic relationships like Clark and Jonathan, Lex and Clark, Lana and Clark, Lois and Clark.