I maintain a fair sized fleet, owning at least of each ship, 2 of many and 3 of some.
Of combat ships, I've a rather nice selection:
Cobra III - Used for raiding + low and medium security installations
Viper III - Used for Nav Beacon hunting
Viper IV - Used for Low RES hunting
Vulture - Used for hunting in Wreckage sites
FAS - Used for ++ and +++ Medium and High security base raids
FGS - Used to hunt anywhere and Low CZ's
Python - High CZ and hunting anywhere.
Anaconda - General combat where large pads are available, RES and CZ.
Corvette - Multicrew hunting and GC's
Beluga - Hunting anything anywhere, any time. Yeah, you read that right, a Beluga. Also as a support ship for training aspiring combat pilots
Orca - Combat Wing Support ship. Light hunting. Yep, you read that right too - an Orca.
Cutter - When I want to hunt but don't want to work at it. See Corvette.