KDF - Vor'cha Attack Cruiser.

With the right build on it. It can take a pounding like a cruiser should. Yet can still dish out as much dps as some escorts. People get surprised by it, when I take it into Ker'rat.
I fly my Vor'cha with stock parts but swap the mission pod around. Depending on what type I fly.
Mirror - Tor'khat pod
Refit - Vor'cha pod
Fleet - Vor'Kang pod

FED - Akira Class Carrier.

Flying into battle with a wing of fighters is always fun. Watching them fly over the ship firing pulse cannons. Reminds me of those Ds9 battles. Plus the Akira just looks awesome.
I use the Thunder Child Saucer and Nacelles, with Stock Akira Struts and Pylons.