I need your opinions to decide what website to make ? 1 - an article directory ? 2 - a social bookmarking site ?
Both niches are over done. Look at what you like and what you are really interested in and have knowledge of. Build a site based on you not based on Adsense. Sites that are original and that you have a passion for will be your best bet in the long run. There are many people chasing the same niche, go original and though it will not be the quick buck, you could have a long term money maker.