for the price, these Sony MDRED21LP Bass Boost earbuds are working out pretty well. they have a little extra bit that penetrates the ear canal, but not as deeply or securely as in-ear models. it helps keep outside noise out but don't bother me in the same way in-ear models do.
overall, for me they're a nice compromise between say the stock iphone/ipod earbuds and the style that came with the Nexus S.
does anyone know if Sony (or anyone) else makes a premium version of earbuds with the same fit as the Sony MDRED21LP Bass Boost ones?