for my babies photos: windows explorer, go by yymmdd the photo was taken, divide into subfolders.
for my other photos, picasa, upload to picasa's webalbum, organized in, well whatever comes to mind. so far I can still keep track of all the photos I've taken.
oh yeah, on dvd for overseas trip, one for wedding functions attended, one for family functions/occasions.
it's really upto you on how you want to organize it.