I like the originals. I'd say pick from the official maps, list found here (scroll down) http://counterstrike.wikia.com/wiki/Counter-Strike:_Global_Offensive

Bomb Defusal

    Aztec
    Dust
    Dust 2
    Cache (became official on July 1, 2014)
    Cbble (released on December 18, 2013)
    Inferno
    Mirage (released on June 12, 2013)[5]
    Nuke
    Overpass (released on December 18, 2013)
    Train
    Vertigo (released on October 1, 2012)[6]

Hostage Rescue

    Assault (released on February 7, 2013)[7]
    Italy
    Militia (released on March 21, 2013)[8]
    Office


Maybe we could hand-pick a few great workshop maps. I'd say they should be either defuse or hostage rescue. I'm gonna check some of them soon.