i always have a seperate make-up bag in my purse, either my coach signature cosmetic clutch or the mac bag that the 5 basic brush set (i think it was patternmaker...it has orange/red/brown/purple diamonds).
it usually contains enough to touch up my entire face, lol. a natural MSF or studio fix compact, stila covered retractable powder brush, black plastic marc jacobs heart shaped mirror compact. rose d'or bronzing stick (i use this as a blush), diorshow black mascara, smolder black eye kohl, lingering brow pencil, sometimes i'll throw a few SE size brushes and a quad with shadow pans in there. also, i have the days worth of lip products, and usually a few other lip things, too, such as minted rosebud, mac clear lip conditioner, and rubia lipstick, always. yeah, i haul around WAY too much makeup.