uninstalling the flash and java plugins would be your best option IMHO... why don't you wanna do that?? anyways, if you really don't wanna uninstall them (because perhaps you want to give the users the choice of using them if they need them for something important) there's always
noscript, which you can configure to block all java and flash unless the users specifically request to enable them for a certain page...
http://www.noscript.net/
just my

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