Using the retweet shortcut in Twitter's web interface is great, but I often find myself wanting to contribute something extra or add a hashtag. Rather than copying and pasting the tweet, Chrome and Firefox users can install this handy extension and gain access to "classic" retweeting.
The extension is straightforward to install and use for both Chrome and Firefox; rather than adding a widget to your browser's UI, it'll modify the page directly so the "Classic RT" link appears right next to all the other options you have when you move over a tweet. You'll then be able to edit the response before it's shared with your followers. The integration is amazingly seamless.
It's a shame this isn't available in the stock Twitter interface. Fortunately, that's what extensions like this are for.