Go to the
OXP download section of the wiki and download some fun!
I recommend the galaxy one specific mission OXPs;
Black Baron, Longway Round, Asteroid Storm, Spy Hunter, Taranis Corp HQ.
Other worthwhile, galaxy independent, missions are;
Random Hits, Military Fiasco, Local Hero, Oo-Haul, UPS Courier
Grab lots of dockable objects, more opportunities to trade/fuel up has got to be a good thing! Best ones are;
Anarchies
Bank of the Black Monks
BuoyRepair
Deep Space Dredger
Free Trade Zone
HoOpy Casino
Military Station
Random Hits
Taranis Corporation HQ
and when you have an iron ass, Pirate Coves
As for eye candy, go for;
Your Ad Here!
Cargo & Wrecks
System Redux
Sung's Detailed Textures
Custom Sounds and Hal's Hot Sister are well worth having too
As for additional ships, well, that's personal taste. You could try Reasitic Shipyards, it adds ALL the new ships, but has some issues. I am nervous to criticise it because its creator is a bit sensitive about his baby... but you do have to realise that it is a very big OXP and will make your computer work hard. It adds ALL the ships, which may be undesirable... you can edit out the unwanted ones, but you might find it easier to just add individual ship OXP one at a time and suck it and see. And finally it messes with the roles assigned to ships, so that vessels do inappropriate things.
Personally I would add stuff slowly, and see if you like 'em. Depends on your style too. If you want to dogfight with interesting foes, add light fighters. If you wand to plunder fat trading vessels, add them.