I want to share with you plugins which i use in most of my WP powered sites and hope they will be useful for you. In comments section you can continue the list and write your favourite ones.
Very useful plugin which lets you to write php codes in any post or page.
2. Quick post
Very useful, easy customazible plugin which allows you and other registered users(authors) to post quickly direct from main page sidebar. It might be used if you use blog as question-answer system.
3. SyntaxHighlighter Evolved
4. Comments vote
This plug-in enables users to vote comments up and down, to choose the best comment of the topic.
5. Google xml sitemap
Very useful plugin, generates xml sitemap of your site and passes it to Google.
6. Peter’s Login Redirect
Lets you redirect users to different locations after logging in. Redirecting sometimes is necessary
7. Facebook connect
Lets your site users to login without registration, with facebook connect button.
8. Twitter for WordPress
Simple plugin which displays your latest tweets in sidebar widget.
Makes wp registration page more suitable.
Helps you to create multilanguage website. Very easy to use.