After only a few years of taking interest in capturing the world about me, I have realized a big problem: To take a good photos requires taking many photos, but many photos means lots of space and more importantly a nearly unsearchable library. Here is the main point:

How does one retain a useful searchable library of photos. Can a GTD type reference section be build from photos in an easy way?

The main classification I have for photos are:
-good photos (artistic, printable, usually posted in flickr)
-sentelmental (not very well done, but they give you a strong reaction, or bring back a memory)
-useful (idientification of something, process, place, I'm in physics, so I have very many data pics of samples etc..)

Some photos fall into several of these, so crossreference is needed.

The programs I'm trying are iPhoto6 (I had 1-2 but they crashed with more then 1-2000 pics) and iView. But I still find that I want an IN Box type format to remember which need sorting etc...

Ideas?