Hi,
I think omega-3 is one of the most important supplements that we should take on a daily basis.
In the book "The UltraMind Solution" (which is an awesome book on how nutrition influences our thoughts, emotions, memory and learn capability)they recommend to take twice at day 1000mg with a EPA/DHA ratio of 300/200.
You can read more of the benfits of omega-3 in a post I have written two days ago. The post it's called:
"5 nutritional supplements that have drastically improved my life".
I hope I have helped you.
Cheers