While this could have been another cookie-cutter Voyager flashback, the episode elevates itself above and beyond the other episodes by focusing almost exclusively on Harry Kim, which was a nice change of pace. I never had really latched onto Harry as a character, but this episode changed my mind for good. Garrett Wang's acting was the strongest it had ever been in this episode, and I was sold on his obsession with fixing the past. He goes through a gamut of emotions and never goes for the melodramatic.
The visual effects are the best Voyager ever accomplished. Watch Voyager's crash sequence and try to tell me you weren't wincing, or that you didn't break out in goosebumps. It was heartrending, and the only other time I have come close to tears watching a beloved spacecraft crash was the death of Serenity in the move of the same name.
Tape it, watch it at a friend's house, buy the fracking DVD set (the rest of Season 5 are stand-out episodes, by the way), and enjoy. Oh, and did I mention it was Voyager's 100th?