Based on last months user survey of  RackWire.com App Market users and overall Feedback, we have compiled our Most Used, and Most Popular WordPress Plugin List, in no particular order:

Sociable – Social Bookmarking made easy.  If you are blogging, the ability to socially broadcast your Posts is pretty important to Broadcast over Facebook, Twitter, MySpace, Digg, LinkedIn, Etc.

Google XML Sitemaps – Create Google, Bing, Ask and Yahoo Compatible SItemaps for your WordPress Site.  If SEO is on your radar, this is an easy and Simple Plugin to use.  Make sure you select Yahoo and enter your Yahoo Application ID.

SexyBookmarks – A great functioning tool to get readers to suggest your WordPress Page/Post to others via Social Medias.  Who am I kidding, I just like the name.

Contact Form 7 – It allows you to flexibly design the form and mail. You can manage multiple contact forms as well.  In addition, it supports many features including AJAX submitting, CAPTCHA, Akismet spam filtering, file uploading, etc.

NextGEN Gallery –  A NextGENeration Photo gallery for the Web 2.0.  My personal Favorite Gallery Manager that is a well written Plugin and easy to use.

WP to Twitter – Updates Twitter when you create a new blog post or add to your blogroll, also can auto shorten Url’s and Pictures.

All in One SEO Pack - Out-of-the-box SEO for your WordPress blog to improve on your Blogs SEO.  A Must Have!

WordPress Gravatars - Uses Gravatars and MyBlogLog Avatars, places Gravatars, OpenAvatar, Wavatar, Identicon, monsterID or MyBlogLog Avatars in the comments section. Uses the comment authors email to display their Gravatar. It also gives the user an Author Profile picture, based on the users Gravatar.

No Comments on Pages - No Comments on Pages is a tiny WordPress plugin which, when activated, disables posting of new comments to all pages and hides existing ones.

Branded Login Screen for WordPress - Branded Login Screen for WordPress lets you use custom login screen instead of WordPress default. Branded Admin which lets you change the admin area is also available.

Twitter Tools - Twitter Tools is a WordPress plugin that creates an integration between your WordPress blog and your Twitter account. It allows you to pull your tweets into your blog (as posts and digests) and create new tweets on blog posts and from within WordPress. You can also archive your Twitter tweets (downloaded every 10 minutes), post a tweet from your sidebar or the WP Admin screens and pass your tweets along to another service.

FB Share –  Adds a Facebook Share button to your WordPress posts, similar to the ReTweet or Twit This Plugin.

This list will continue to grow, as there are many talented Developers out there.  Happy Blogging!