Thank you for your help guys. Things are a little clearer.
Would you always use the high res images when adding photos to your photo app on your PC/Mac (ie: iPhoto, Picasa etc.) ?
To be honest, I usually upload all photos taken on the phone directly to facebook, which are the low res images.
However, I'm one of those people that keep EVERY picture I've ever taken, so regularly I'll dump the high res images on to a folder on my server just for the sake of keeping them. As far as I'm concerned, the low res images are disposable, but the high res are considered gold.
I don't know what iPhoto is, but as far as Picasa goes, in my case it indexes and uses the high res copies I have on my server.
One more thing I normally do: When I move the High res off the phone, I actually move (I cut/paste, instead of copying). This keeps my memory free for new pics, at the same time allows me to keep the low res older copies in case I need to show anyone!