Should I seed directly or sprout and transplant
 

I vegetable garden organically in Oly, Wash. and am getting ready to
start this year's crop. I have good soil and good compost to enrich
it with. Opinions: should I seed directly or start and transplant?
Does it depend on the plant, i.e., some plants should be seeded
directly, others started and transplanted? And any opinions regarding
using egg cartons for the starts? Finally and separately, any advice
on nursing transplanted cedar sprouts?