I run Valvoline conventional 10W-30 with Purolator or Motorcraft filter (Never any additives). Change both about every 3000 miles or annually, whichever is first (I know the trend has been going more toward longer change intervals, I do it because it's a 2nd-vehicle 4x4 play toy and sees very dusty conditions most every time it gets driven).
Mileage (equivalent) is probably around 270K... ODO just rolled over for 2nd time, but I did have the speedo cable disconnected for some time after the doubler went in, plus all the hours & hours of driving in low range that doesn't rack up the ODO as fast as being on a freeway does.
If you are storing it, change all the fluids, drain all the fuel out and run it till its out of fuel.
Or if you are able, take it out on a drive at least once or twice a month.
That is what my dad has always done with our RV. About every two months, if it hasn't been driven, he'll take it out on an early Sunday morning when there's no traffic and jump on the freeway for about 10 miles while also exercising all of it's systems (generator, A/C, etc.). Seems to do OK for it, we've had few issues with it sitting other than the occasional spider making it's nest in the flame tubes of the heater, fridge, etc.
If it cannot be driven for a few years though, then what I've heard is put ½ teaspoon or so of oil through each spark plug hole, and then spin it over a few times with the starter motor (ignition disabled). Then all the usual stuff such as draining gas, having fresh oil in the engine itself, etc. Wouldn't hurt to have fresh fluids elsewhere too, such as transmission fluid, coolant, power steering, brake/clutch fluids, etc.