Jaundiced travelers often dismiss the Khan al-Khalili as a tourist trap; there's no ignoring the fact that it's a favored stop of tour buses and has all the associated annoyances (touts and tat) that come with them. But it's worth remembering that Cairenes have plied their trades here since the founding of the Khan in the 14th century - the buying and selling didn't begin with the arrival of the first tour group.
Today the market still plays an important role in the day-to-day commercial life of thousands of locals. In its narrow streets you can buy anything from shoes to souvenirs to clothes, chess sets, cushions, ceramics, brass, gold, silver, rugs, fabrics and on it goes.
The Khan al-Khalili is in the center of Cairo and the easiest way there is to grab a taxi. The most important thing to take with you are your bargaining skills. Leave a few hours to really explore.