I love my Canon EF 24-70mm f/2.8L.  

When I do portraits, it is just my workhorse.  It gets the job done so beautifully.  Just the right amount of zoom, fast enough to catch moving toddlers in relatively low lighting, when zoomed in makes loverly bokeh....Captures lovely scenary...I just love him.  Yes...it's a him.  His name is Hardy.  I have another smaller lens named Laurel. :P

Someone once told me you could turn your regular lens backwards and use it as a macro lens, but I've never tried it.

However, the first lens I would buy would be a macro, im obsessed with taking super close ups of little things.