Gmail Labs adds new Reply add-ons

Official Gmail Blog: New in Labs: Reply add-ons

Gmail Labs has added three new reply features.

Quote selected text
When you just want to reply to one small part of a conversation, deleting lots of irrelevant text is rather annoying. This Labs feature should make your life easier. Just highlight the text you want to include in your reply, hit the keyboard shortcut "r" to reply, and the compose template will be just what you selected!

Note: This doesn't quite work in Chrome or Safari yet, but it will in a few weeks.

Default 'Reply to all'
This Labs feature, which makes reply all your default selection.

Vacation time
This function lets you compose and schedule your vacation autoresponse while you're planning your vacation, rather than while you're on vacation. And scheduling is as easy as it is in Google Calendar.

Read the complete post at Gmail Blog.