For my fretted basses I use rotosound swing bass 66 strings: Tone, Feel, and Durrability. They actually sound good right up until they break.

I haven't decided on a brand of flatwounds for my fretless yet... I have fenders on it, but I'm going to ditch them sometime soon.

On my guitars I use GHS Boomers .012-.05something w/ a wound G string. They last a long time and sound great.