A number of plugins are instrumental to the daily functionality of PSS:
LinkWithin – a related posts plugin with thumbnails
Contact Form 7
Fancybox for WordPress
Faviroll – Favicons for the wordpress blogroll
Greg’s Threaded Comment Numbering – For those fancy numbers in the comments that enable you to participate in giveaways!
Smart Archives Reloaded
Twitter for WordPress
WP Render Blogroll Links
WP Super Cache – the one, the only!
Also instrumental to Pretty, Shiny, Sparkly’s accessibility is the ever-fabulous and superfast (and supercheap!) web hosting company, InMotion Hosting. I heart them! Here’s the plan I’m on (just $6.95/mo!): Business Power.