I also strongly recommend the Vit. D3 - I take it every single day. I actually take 5,000 IU, but I'm no doctor. I can't remember where I was reading that was a reasonable dose (it's been over a year). I had bloodwork done about 6 months ago, and my levels were in the low side of normal.

I can tell a difference in my mood when I don't take it for several days.