Steroids - Not worth the side effects, why risk wanting to get a chubby tubby, saggy breasts, increase in aggression, smaller and messed up testicles and penis etc just to look "good" fast.
Creatine - Works for some, fails for others, its not as dangerous as steroids because our body produces a bit of it so its natural, but taking in too much can cause liver damage. If you are going to take this, make sure to drink a gallon or two of water per day, few of my friends took it and even with two gallons per day, they told me their piss was like yellow gatorade. Make sure to take time off before going back to it at regular intervals.
Protein Supplements/Weight Gainers - No, experts say these only work to a minimum effect. I've heard a few guys who say they got bigger from it, but they haven't considered that maybe the fact that they ate a lot more and worked out better might have been the significant contribution. I took protein shakes and stayed at a constant 155 pounds your height while working out for almost 2 years. Then I researched how to better work out and eat last spring semester, did NOT take protein supplements, became a personal trainer, and am currently 170 pounds as of two months ago. I think I probably gained more weight by then, but its all good. I'm aiming for 175-180.
N.O. Xplode - A recent "miracle" supplement I've heard within the last few months, sounds pretty cool at first. I might try it out just to experience it (sounds like drugs haha, but I don't do any). Supposedly it opens up your veins and arteries so that blood flow will increase significantly, which I think is true from what everybody told me has taken it, which means they can work out more effectively and with more weight due to the oxygen flow. Pumps you up and makes you feel like doing nothing else but working out for hours a little while after you take it. No known side effects at the moment, other then that you can't sleep if you taken it at night time. That part doesn't sound safe, it must have a lot of caffeine or something to do such a thing. I don't mean like coffee, if you drink this at 10pm, you wont be able to sleep even if its 6am and worked out through most of that.
In general, supplements are bull, I don't mean every one, but hey its business, they know the guys want to get bigger and the girls want to get smaller, make a pill, call it something flashy, get/pay somebody that sounds certified to say its approved/guaranteed for "blah blah blah", market it, and boom everybody wants a piece, the businessmen go mwahahahaha look at these fools while their profits increase drastically.
Drugs like steroids, they work, they will get you bigger and suddenly bench like 300 pounds, but anything fast achieved is never without its penalty. It's either fake water muscle that'll disappear, a peepee that'll get smaller and look microscopic compared to the rest of your muscles, heart failures, etc. Watch Star Wars, what you think they are trying to convey about the Jedi and the Sith (who try to gain power quickly by "cheating" all of them turn out messed up, crazy, or ugly like the Emperor) =).
Well it seems there are some other personal trainers or future personal trainers here, ask them or me first and see if they can correct any possible mistakes with your diet/form (just for your info, the knowledge personal training certifications give us[unless we had learned it ourselves] on dieting is general and limited., go to a nutritionist for proper ways to eating healthy, we can only tell you generally what you should do about food. We specialize in the exercise, not the munchies, many people have that preconception of us wrong.) Try it out, if all else fails, you can take your steroids and get smaller testes if you wish =).