I just looked Centrum up. It's a pretty cheap brand. That definitely brings its quality into question.
Assuming you are a guy, men generally get all the iron they need from meat and it can possibly build up if taken in excess. A lot of vitamins for men are iron free or low in iron, while Centrum has 100% rda of iron. Just something to consider...
A few supps to take besides your Centrum multi:
fish oil (1-2 grams dha/epa a day)
magnesium (400-600 mg a day - Centrum is very low in magnesium and there are better forms than magnesium oxide, which it contains)
vitamin d3 (2000 IU - Tough to know for sure as age, skin color, uvb exposure, etc all play a factor)
A few other useful supps, depending on how much money you have to throw away:
coenzyme q10 - (25-100 mg a day)
acetyl l-carnitine (100-500 mg a day)
alpa-lipoic acid (50-300 mg a day)
taurine (1 gram twice a day)