In general I would agree, although there are a few web sites that require it. If you have to/want to visit those sites, another way is to use your browser’s controls to disable Flash except for those specific sites that need it.
In Firefox, click
Tools -> Add-ons. Then click the Plugins tab (left side of the screen). Set Shockwave Flash to “Ask To Activate”. When you visit a site that has Flash content, you’ll see a red plugin icon in the location bar. If you don’t want the Flash content to load, do nothing - it is being blocked. If you do want it to load, click the icon to enable Flash for that site.
The only problem with this approach is that when in the “Ask To Activate” mode, Firefox reports that you have Flash capability. I suppose it has to do this, otherwise the remote site wouldn’t try to serve Flash content and the browser wouldn’t put up the icon you need to enable Flash (should you want to). The downside is that sites may not try to serve a non-Flash version of their content, if any exists.
For this reason, I configure my Firefox to completely disable Flash (“Never Activate”) in the add-ons preference screen. I manually enable it for those rare occasions where I actually need it, and then turn it off again when I’m done there.