For WW1/WW2 I guess it depends on what level you want to play. I use a wide variety of rules across many levels. So for fleet actions I tend to use General Quarters, for smaller actions when i have a bit more time and I want more detail then I use a derivative of the old Skytrex WW2 Naval Rules from the 1980s. For similar level games that are faster and suited to nwbie players then Mongoose Publishing's "Victory at Sea" (WW2) or "Age of Dreadnoughts" (WW1) - both of which I had a hand in writing. And then for coastal forces games I use my "Action Stations" CF rules which have been on the streets over 20 years now.