You can get into an EOS-M system quite cheaply now, $299 gets you a body and 18-55 lens. An adapter lets you keep using your EF lenses.
It's either that, or m4/3. I am a Canon DSLR guy, but Olympus and Panasonic have been keeping the m4/3 format quite competitive IMO. The EOS-M has its problems; it its AF is slow as hell, and its touchscreen UI is lacking, especially if you're used to Canon DSLRs. With m4/3 you have a good selection of bodies and lenses, and the AF on newer bodies is quite fast; slower than a DSLR, but not bad at all.