My fleet comps are often eclectic, with a focus on having lots of "anvils". The few "hammers" I keep are either SO, my flagship, or the Desdinova/Nevermore/Kormoran. I also always have a Shepherd and/or Katrina, as I will never pass up salvage. I rarely use capital ships, and if I do I usually go with an Odyssey or Conquest first. I've only used an Onslaught once or twice, and I always hate it. If I want a full battleship I'll grab a Mimir or Paragon.
My Desdinova/Nevermore/Kormoran/Odyssey/Mimir is piloted by me, and when I move on I keep them as back-up ships or specialty fighters.
I usually have the following ships in my fleet at some point, faction runs aside:
2 or 3 Wolves: Very flexible harassment frigates with Harpoon/Sabots and Phase Lance. I later use them as pursuit ships with Pulse Laser, Ion Cannon and Salamanders.
SO Lasher/Hammerhead/Vindicator: Perhaps my favorite SO ships, the Lasher and Hammerhead are usually my flagships early game, with an SO Vanguard with a Devastator sometimes substituted in. Lashers use Dual MGs and Vulcans, Hammerheads use Dual HMGs plus Vulcans. Both carry Perforators/Annihilators.
SO Eagle: I've only recently been doing this, but an SO Eagle is soooooooooooo much fun. I blame the tournaments for these. I usually equip with 3 Flamers or 2 Assault Chainguns and a HMG in the front slots, 3 Storm Blasters or Ion Pulsers (interchangeable) in the energies, normal PD lasers for PD, and Annihilators/Perforators/Quills for Missiles.
4 or 5 Moras: I keep several of these loaded with different missiles. Fighter-wise I usually go with Talons, Khopeshes, Spirales, Sparks, and Flashes depending on the missile choice. (Khopeshes or Flashes with Sabots, Talons or Sparks with Inferno MIRVs, Spirales I'll put with Harpoons or any other missile because I like them)
Corocotta: SCY ships are a rarity, as I never really visit Tartarus except for Frism Preport. I sometimes get lucky and snag one of these. I give them a HEMor/KAcc with the secondary weapons being the alternate versions. I once had one with a Zone Scorcher and was very happy with it. Until it died.