I would like to support what Caolite has said about his girls experience of SL - exactly the same for me.
I've tried just about everything to improve my SL experience, but am constantly reminded that I am at fault somehow for either my ISP, my wireless, my computer or my understanding of technology generally!
I have seen many others forced into thinking a "better" computer would solve crashes and FPS problems or other related matters, only to spend a fortune and get bounced off sims repeatedly OR their ISP from the UK won't "speak" to the US servers. I have had whole evenings where a bunch of friends from the UK all fail to hear a concert OR can't log in - then other evenings where we are all ok, but German friends keep getting bumped out or can't gain the media for music.