Found two new bookmarklets, thanks to Jono.
GmailThis: This is a nice bookmarklet that helps you to mail the current URL you are reading through gmail. Try it out.
BlogThis: helps you blog easily without having to enter blogger in a complex way!
Also there are bookmarklets for bloglines and del.icio.us.
Talking about Hacks - check out the RSS hacks. Will be really useful hacks if you know about RSS.
Make my life easy atleast!!