WARNING: Kabul is currently extremely dangerous and sudden changes can occur in the security situation. As of April 2012 there has been extensive terrorist activity in Kabul, including suicide bombings and attacks on embassies. If your visit is essential, consult your country's embassy in Kabul and monitor US Dept. of State & UK FCO travel warnings throughout the planning and duration of your trip/stay.
Kabul is generally considered one of the safer parts of the country, and while bombings and kidnappings have waned considerably, they do remain a threat. That said, there are tens of thousands of expats and visitors to the city and considering that only a small handful have been victims of such attacks, you should be vigilant but not afraid. Avoid walking after dark, don't loiter in hotel lobbies, and for long stays and expats, vary your routes and timings daily. Riots happen occasionally and are often accompanied by looting -- stay well away from them as authorities will respond with lethal force.
Female visitors: Make sure you wear a headscarf before landing in Kabul Airport until you fly out.
While visiting Kabul or any other part of the country, having any kind of social interaction with local people should not be a problem, Afghan people are traditionally very kind and hospitable toward guests.
Read the Scene magazine for restaurant reviews and all sorts of useful info. It is free, although street sellers may charge for it. There are many FM radio stations. However, the only widely available English language broadcast is from the BBC World Service on 101.6MHz. Tolo TV is perhaps the most popular TV station.