Sometimes you want to selectively get rid of the breadcrumbs. They just look strange with some page configurations, and now with the Disable Breadcrumbs module you have all kinds of ways of controlling them. You can get rid of them "on a per node, per content type, or by path (any path) basis" and they will look fine everywhere else.
Boost is recommended to help with caching in Drupal 7 for "anonymous" traffic. That's users that aren't logged in. I installed it here at PcHousekeeping a few days ago and it really seems to have picked up the speed.
The super support folks at KnownHost installed Memcached for me today on my VPS. I also asked for the PECL Memcache libraries and they got the latest stable version which is 2.2.6 at this time. Did I need it? No not for this little site with light traffic, but I had to see how it all worked so that when the time comes I will know.
One of the first things I have seen when looking at YSlow and Pingdom reports is the need to serve files that change little from a CDN (Content Delivery Network). Using the CDN module for Drupal 7 worked on one site, but here at PcHousekeeping it just wouldn't play right. I found a good tutorial by Wim Leers the developer of the CDN module and it encouraged me to use commercial CDN service.