Performance Optimization Modules [WIKI]

Hi (This is a WIKI -- please edit as you see fit)

I thought I'd create a Wiki listing of all modules that can help beginners and intermediary drupal users (like myself) to optimise their websites' pageloads. Please enter the modules that you are familiar with, and few words of description/review/rating would also be helpful.

CDN integration -- Offers the ability to serve static files via a Content Delivery Network. As mentioned within the project page it does not seem to be ready for production use.

Boost -- This module provides static page caching for Drupal 4.7 and 5.x, enabling a potentially very significant performance and scalability boost for heavily-trafficked Drupal sites. Has anybody used this? What do you think?

Cacherouter -- any reviews?

Javascript Aggregator -- This module aggregates all your .js scripts, reducing the number of necesserary downloads. It can also delete any unuseful characters (commentaries, unuseful blank spaces...). It provides the possibility to exclude some scripts, because some of them may cause problems (test it before enablig on production). In fact, this is the same functionnality than what already exists in core for CSS.

CSS sprite generator -- still in dev. Any reviews?

Advanced Cache -- Brings caching in Drupal to places where it is historically unavailable.

Memcache API and Integration -- An API for using Memcached and the PECL Memcache library with Drupal.

Block Cache -- a module that creates a cached version of each block.

Any other modules that you know of?

Adding best articles, handbook pages, tweaks, would also be helpful

Please add the modules that you've tried and put the ones you recommend most at the top.