Although I am relatively new here, I've seen my days worth of over the top, unpractical, trillions of credits worth, kilometer long and 10 million tonnes fat ships, I haven't seen a lot of actually practical ships. I'm not a new player, but I'm not too experienced (3 years of GalCiv and 1 of GalCiv2), I haven't gotten to the point of mastering the ship builder and building truly magnificent eye candy. But I have made many practical designs before.
My current game as the Dominion of Korx (Large galaxy, 7 opponents, Normal), I have designed 3 ships to be the main stay of the fleet of my current technological capabilities. First up, is the Dragon Class Heavy Assault ship. It's role is to pwn.

Next, I have here the Sovereign Class Ship of the Line. It's more or less modeled under the role of the Sovereign class that we're familiar with in Star Trek, moderately armed, moderately protected, fair speed and range, sensors for exploration, etc.

Finally, my favorite class of ship is the Penguin class Battlecruiser. It's description is dated (as I've upgraded the Service model with an Impulse Mark III engine, 2 high-yield beam arrays, and gave it it's Deep Strike Capabilities.) Personally, I see this as one of the most useful ships out there, it's relatively cheap (270 billion credits), long range (63 parsecs), fair speed (5 parsec/wk), and decently armed (beam attack of 6). I think you should all buy this.

So that's about it. Anybody else have any "practical" ship designs to show off? Something you actually would use for a game en masse or when you start off in a bad position?