for maru:
Pyth: super low upkeep, reasonable initial build cost and great shields/weapons
Angel: to kill guard. Also great upkeep. cost is reasonable once your settled.
Pike: reasonable cost and upkeep. No mineral cost. Long range and best weapon damage combo in the game (IMHO) when matched with long range it`s a sure winner
Terran:
herc: It`s really a no brainer. Good spam ship and decent for fast retals.
Tyr: Again almost exactly like the Angel, just cost alot more in minerals and upkeep. You need it to kill guard and some others.
Other is your choice for terran.
Miner:
Flych: General great all rounder with reasonable mineral cost (80 rutile is danged cheap for what it can do!). Decent range and weapon damage spread. Keep away from missile toting ships however.
Arg: My personal favorite miner ship. Great shields except for kinetic (-60% hurts! Keep away from F class and Pikes..they walk all over this ship!) High upkeep but will take a beating if not met with kinetic damage
Epitode: Range 9 Energy ship. Great for that Queen spam kill or just general first shot chiron spam kill. All round a good ship. Reasonable build speed, nothing fantastic but after all it is only a destroyer.
Chlorite: range 9 missile boat. good for killing borries, pyth and anything weak to missile damage. It meets queens or runners however and it is toast so keep an eye out. Still a good ship. Take it if you thihnk your missing missile long range power.
There are more I could list but Ryu Jin spams are nasty low PR but high PR they are tedious to build, illum are good hull but agian take ages to build. Nirv are a great ship but you have Flysch and Pyth that do the same thing that they do with the cheaper upkeep or cheaper mineral cost (not a big thing for established empires but starting out it`s a factor in choosing).
Hope this helped.
There are lots of people that will recommend other things but use what you like most from the races really.
Go