The lively Black Cat is a local favorite, as any Hyannis Porter will tell you.
In addition to having an extensive seafood menu (I've heard they buy their fresh catch TWICE a day), The Black Cat can also fulfill carnivorous cravings if you're in the mood. I was, and enjoyed a delicious and hearty rump steak--as thick as the span of my hand--while sitting at the attractive bar. The bar, by the way, has excellent nuts and great single malt Scotch--I was with an expert. As to seafood, you'll find a wide variety of local specialties (lobster, cod, chowder) as well as some interesting pasta items (Swordfish Piccata – "pan bronzed center cut swordfish with fresh spinach in a lemon caper butter sauce over angel hair").
These guys know what they're doing--I found the service both professional and friendly.
The vibe is a bit on the upscale side and very festive--a great place to enjoy a meal and kick back a drink or two. Perfect for a group or a date--check to see if they'll be having music and dancing the night you dine. Great location by the harbor near the Steamship Authority.