Currently you have a color scheme based on similar brightnesses of very similar hues—green and blue are very close together on the color wheel, thus it's difficult to tell them apart and in some sense they "clash" with each other.
The grey you've chosen is also very similar in brightness, which makes the whole theme quite low contrast, and thus difficult to read.
Analogistic color schemes like this can work, but they need to be relatively high contrast so that there's enough of a difference in perceived color to make text readable and transitions more clear. And to prevent clashing, which is just generally perceived as unpleasing.
I'd go with your little memory-chip icon. Take the green off of that (#60B660) and the chip grey (#424242) and choose a contrasting accent color. You can go with a blue, but I wouldn't recommend it, and if you do I'd go with either very dark or very light used in places where it won't clash (such as maybe the top nav bar). Against the green, I'd use an orange or red or magenta in there, or just go with one main color and adjust brightnesses as needed (pretty failsafe).
It's hard to explain how good color schemes are really created, other than by following the color wheel somewhat and your sense of aesthetic above all, but you can take any of these as a start for reference on what's "good." -- http://www.colourlovers.com/palettes/most-loved/past-month/m... -- Yours isn't too bad, there's just something off about it due to the low-contrast high-similarity colors used. Cheers.
