Twitter has released a new feature for iOS, web (and soon Android) users of the service that will separate quoted tweets from your own commentary. This change should make it easier to quote various tweets without having to sacrifice on context or redirecting followers to external resources.
Retweeting with a comment will allow you to embed the quoted tweet without having an impact on your character limit. The feature is available for everyone on the website, as well as iPhone app users. The official Android app will be updated soon with the same feature.
Unfortunately, embedding a tweet on a web page does not pull the quoted tweet – you'll have to click through on embeds to see the conversation. Also, there's a limit of one quote per tweet, so don't go trying to pull off an Inception on us.