Hi Peter,
> From a security point of view, am I opening up my PC to greater risk
> of attack by installing Shockwave ?
No, but most of todays Shockwave animation are actually ads. And a large
fraction of them is very annoying. They occupy your web browser screen like
a new layer obscuring the actual content of the website. You have to
actively close this kind of ads or you are forced to wait some seconds until
the ad finally decides to go away (if at all).
If you decide to install Falsh consider installing a Flash-Blocker too to
keep the control over your web browser.
Viktor
http://www.quero.at/