Primary photo storage is on a RAID5 array of 4x2TB HDD, where photos take up about 1.5TB of that space at this time. At the same time, unless they are just me screwing around with the camera, the photos are also copied to a USB HDD attached to the same machine.
Important/favorite photos I would prefer to not lose are subject to duplication on a budget RAID1 NAS locked in a rack in another part of the house - This is probably 30% of shots.
Special events and special holiday photos after sorting, the good stuff is copied to a USB HDD and kept in my desk drawer at work.
In some cases I also burn archive grade 100Year DVDs - But that's generally the favorites of the critical stuff - ie, what I have already printed.
I'm not shooting enough to need to filter shots within events at the moment - If I decide it's important, the entire directory for that shoot undergoes the same management. But I am getting better at culling worthless shots on the initial import, no need to waste 80MB/shot when it's unusable.
A device so simple that it took a mind as brilliant as mine to create it! So brilliant, in fact, that simply by harnessing the power of one live frog, it... it... uhh... <poke> <poke> ... World domination has encountered a momentary setback. Talk amongst yourselves.