What's the best primer for exposed woodwork?

I recall reading the following a bit back in response to a similar query - 'Primer on wood usually fails due to fungal growth on the surface, lead primers were better as the lead content was slightly poisonous to fungus, so modern primers never as good' - or words to that effect. Though I knew a painter that wouldn't even consider any sort of wood preservative as it made paint less likely to stick. New wood certainly keeps paint on better.