I know this post is a bit old, but Dev HTTP Client for Chrome is by far the best plugin I've found.
Along with providing a nice UI that pretty formats responses (like JSON and XML), it allows you to save any requests. IMHO, the best feature is the ability to set different "contexts" and set variables. For instance, you can have a "production" and "dev" context, each with a "host" variable. Then your request string could be http://${host}/foo
.