Suikoden 1 one time since it came on PSN, will play again soon.
Suikoden 2 three times, twice when I owned the disc, once since it came on PSN.
Suikoden 3 I'm currently on my sixth separate playthrough. It's by far my favorite.
Suikoden 4 twice, once when it released, another when I rebought it and felt like torturing myself
Suikoden 5 Once so far. It was a good game but it's so heavy with the cutscenes it took too long to finish.
Suikoden Tactics Haven't played it yet, just recently got access to it, will probably give it a look.