First of all, getting bored is not a serious threat. As long as you get result that should entertain you. Second - running into a plateau is not the end of the world. I generally find that I need to change things if I haven't seen any progress for four straight weeks.
Bottom line: Stick to it for a bit longer.
Here's what I'm able to comment on...
Muscle Gaining Secrets: works fine up to a point. It takes some experience to make split squats effective (since you must not make them about lifting AMAP - that will just lead you to cheat).
Stronglifts 5x5: works for a while. My knees hate me if I squat 3x/week. And I mean in the "we'll stop working if you do this" way.
Mass Made Simple: like a charm. But you need to devote your life to it for six weeks and it will be uncomfortable.
Westside for skinny bastards: good strength gains, somehow I found it hard to gain mass. Maybe that was a diet issue though; I'm always amazed at how much I can eat without moving the scale.