I don't really believe in rigged series but if there was one: OKC/LAC last year. Durant and Westbrook got every whistle. They shot more FT's than the entire Clipper team in the last 2 games. Still remember when Westbrook ran into a ref and Paul got called for a foul.
Everybody complains about the 2006 finals but that series was worse.
Re: Top 5 rigged playoffs/finals series of all time.
Lakers/Kings 2002, I've never seen anything like that.
LeBron has definitely gotten favorable refereeing through the majority of his playoff runs but 2002 stands out to me. The 2012 finals were pretty bad, Toronto/Brooklyn last year was bad (I'll admit my bias as a Raptors fan), 2006 finals as well.
Though I didn't see it when it happened, the phantom foul against Laimbeer back in the late 1980s (exact year?) in a Pistons-Lakers finals was bad, though it's more difficult in that case to argue rigged than it was in 2002.
I'll be honest though, I have very little faith in the integrity of NBA officiating in general. I watch the NHL/NFL/MLB as often as possible, the latter two more often than I watch the NBA, and although there are individual games where I'll blame the officiating for the result I've never thought that the game was actually rigged. The NBA is a different story.