Can you suggest a hair dye to cover greys?

Ok so I have a few greys. Does anyone have a preferred over te counter brand that has good grey coverage? I tried garnier, and it didn't do so well.

Any suggestions would be greatly appreciated.

I just use the schwartzkophf ones in my natural colour (dark brown) and they work well.

I have used loreal preference, it has worked a treat.

My natural colour is dark brown too.

I forgot to say I have used a revlon permanent colour once and it was terrible! It made my hair feel like straw for weeks afterwards. It was only that I had a haircut that it felt normal again.

I go to hairhouse warehouse and get the professional hair dye. It works out around the same as supermarket brands cost wise but the quality is soooo much better. I (thanks to terrible genetics) have loads of greys and the dye I get always covers them no problems. Now if only I could prevent the regrowth coming through grey too...