>I do know that the first thing to do is to go through your collection
>and dump what is not worthwhile keeping.
I'm not sure why you say this in such an authoritative tone, but this is a great example of something you *shouldn't* do. There's nothing to say that a shot that you're not particularly fond of today will remain so forever. This is especially true when you shoot in RAW, since there's so much to work with and techniques you can learn to salvage a so-so picture.
Moreover, your attitude of 'I have a laptop with an internal disk and don't wish to change' is a terrible one to have. If your data's security is important to you, you'll need to expand your horizons quite a bit.