Energy levels shouldn't be affected with a basic multi vit (except as court said below) - you may also get some increase indirect energy increase if you take higher levels of B12 as that can increase appetite (most often noticed if you inject B12, I've not seen it with pills myself). Pills are basically an insurance policy. If you are suffering low energy I'd consider your actual diet first. Food is your fuel source, so low energy means that you are probably not eating the correct stuff you need. Look at your diet, look at your water intake, look at the amount of rest you are taking each day.
I take a cheap, basic multi from healthspan nothing world shattering. I take other stuff separately, but that's purely an option I choose to take.
If your energy is low cover the basics first, here's what I'd suggest you look at:
Total calorie intake - make sure you are eating enough
Ground flax (or other omega-3 essential fatty acid every morning)
Green leafy veggies at least 2 meals a day
Coloured veggies at least 2 meals a day
Whole fruit daily
Try to get most calories from whole food as you get a lot more nutritional density from unrefined foods
Try to cut down on sugars & white flour products as these can cause sudden drops in blood sugar levels, whole foods will do you much more good
If you're training consider where you are getting your protein from, consider having a protein shake if necessary (soya, pea, rice, hemp, or whatever you prefer)
Make sure you are getting enough water, although I can't give you an exact figure (as situations vary), here's a very rough guide:
Sedentary cool 2-3 litres
Active cool 3-6 litres
Sedentary warm 3-5 litres
Active warm 5-10 litres
Ultra-endurance or people training or working for many hours may also need to think about adding electrolytes to that intake so you don't urinate/sweat them all away!
Hopefully check that will help you find a solution?