Take a ferry over to Amsterdam North for some nice running variety. North Amsterdam was a historically industrial area, but has gradually transformed into an arts and cultural area, with trendy galleries, cafes, and restaurants. It is a lot less crowded and touristy here. The waterfront area is great, with great cafes, the EYE Filmmuseum, pleasant neighborhoods such as Nieuwendam, Ransdorp and Zunderdorp, and great parks and waterside running. The best bet is to start from the ferry terminal, right across from Central Station (ferries every few minutes) and follow the Buiksloterdijk along the canal, through Noorderpark, crossing the A10 and then looping back through Baanakkerspark and Vliegenbos. For an even longer run, once you are north of the A10, there is great terrain for running.