Bayonetta & Persona 4: The Golden are recent ones for me. I didn't really expect much going in, but ended up really enjoying them. I still haven't finished either one, but so far they're both excellent.
Animal Crossing: New Leaf is another one. I had never played an Animal Crossing game before, so I wasn't sure what to expect. I got hooked though, and its currently my most-played game on my 3DS! xD