Which grado and what is your price range? What part of the sound do you like?
Most good brands (thiel,Wilson, B&W, Focal,dynaudio, etc) will out class your grados. Grados are bright and forward with little bass extention. But they are fast and dynamic.
Look for balanced speakers that lean toward the forward side (Thiel, Wilson Audio, small Focals 1027,1037) for a grado-ish sound. If you are tight on cash give Klipsch a go.
Brands that sound nothing like grados (and more like Sennhiezers) are Dynaudio, Sonus Faber, etc. They are neutral but lean toward the dark polite side.