i use lightroom, currently version 4.3, on a macbook pro, and i too follow a very similar workflow as scott, i am a little more haphazard in the beginning as i always import from the card to an external drive, which one depends on which one or ones it took along on the trip. i have a pretty large supply of cards, and am always adding to my supply as cards get bigger and prices drop. i do this so that on a long vacation with the potential for thousands of photos i have enough cards in a large enough size so that each day can have it's own separate card. i do this so i can return home with the cards still intact, so if i have a drive failure at any time prior to final backup i will not have lost that days photos, i may have to completely redo the workflow, but i still have all the originals to do that with. i put basic keywords onto the files, plus copyright metadata during the initial import, my next step is the first cull run through, getting rid of the real dogs for good. nnow when i download i will set up a folder named by year-destination. such as 2012-pixelmania. then within that during import i import by day to subfolders labeled by date, and in the case of such as the alaskan cruise by some distinguishing feature. date-skagway. i batch process as much as possible in lightroom, adding further keywords specific to the subject matter and deleting those that did not make the second cut. i also batch rename the finalists , and lately have been numbering them in sequential order. when i am done i upload the finished ones to my phanfare site, followed by some to flickr, there it's more specialized as i have just a few collections of specific stuff, such as my ongoing quest for all the major league parks. i then export all the keepers over to my netstora twin hardrive cabinet in original form. the lightroom export function allows for setting up subfolders and choosing format, such as dng, original, jpeg, psd.
it may seem like a lot of work, but once you develop a workflow that works for you, and if you keep to the steady naming conventions, and really really tag with keywords, you can then in lightroom/aperture and i'm sure many other editors find specific photos very very easily