Microcenter in Cambridge has expanded their space for DIY recently, and is decent now for hobby-level stuff. They have a very large selection of various kits, RPi and Arduino shields, sensors, and some tools.
They don't have very much single-component selection -- although, to be honest, YDI Electronics selection is kind of limited too (understandably because, well, internet).
They don't have very much single-component selection -- although, to be honest, YDI Electronics selection is kind of limited too (understandably because, well, internet).