you probably also need a way to send a headphone mix,
either from a dedicated bus or even the L/R mix if you're recording up to 2-3 sources.
some interfaces have everything you're looking for,
but it's also possible to get a card with less features and combine a mixer for the rest (i.e pre amps, monitor outs, headphone outs, a few more simultanous sources etc.)
also, IMHO it's better to stay away from cards that require alot of jack-minijack, xlr-stereo jack plug type converters (and definitly any minijack input for important sources).
they're unreliable and you never find them when you need them.