TuniLame

You will be able to configure the color, size, link and link’s target of each button and even add a defaut button for many posts. 
To use it, just take a look on the plugin’s configuration page which contains all the informations and settings for the default button. 
Add the button by using <code>[button color= size= link= target=]text that will be shown as button's value[/button]</code>
Attributes that can be used: 
* color: There is 7 different colors: pink, magenta, green, red, orange, blue and yellow 
* size: There is 4 different sizes: small, medium, large and super 
* link: The link of the button. Example: Your site’s URL http://mysite.com 
* target: The link’s targeted window, can be: blank, new, parent, self or top 
Exemple: <code>[button color=blue size=super link=http://twitter.com/tunilame]Follow me![/button]</code>
Simply add <code>[button]</code> in you posts when you want to use the defaut settings.

CSS3 Buttons

Add coloured CSS3 buttons on your posts using simply a shortcode.

Nick Halsey

This plugin automatically adds CSS3 transitions to your website/blog and the WordPress admin. Links, etc. get animated transitions between their normal and hover states. CSS3 Transitions are supported by the most recent version of every major browser (Chrome, Internet Explorer 10, Firefox, Opera, Safari); browsers without support will continue to render everything as they had before. This plugin adds the transitions (eye candy) to all <code><a></code> (link), <code><li></code> (list item, usually used in navigation menus), <code><img></code> (image), and <code><input></code> (form field and button) tags that have a hover or focus state defined (for example, if links change color when the mouse hovers over them). Other “buttons”, form elements, and WordPress-specific selectors are also targeted. Transitions are between .2 and .3 seconds in duration, so they shouldn’t cross the line between nice and distracting; however, depending on the colors used in your theme, the transitions may not be noticeable.
Also, please note that image sprites simply don’t work well with blanket css3 transitions. If you see wierd animations where images scroll between their normal and hover states, they’re using sprites. Depending on where the sprites are used, there are various ways to prevent the behavior on those elements, while retaining transitions where desired. One method is to add an inline style attribute to those elements: <code>style="transition: none; -webkit-transition: none;"</code>. Adding the css to your theme will override the plugin’s css as long as you target the elements using sprites by class or id.
Please feel free to offer any feature suggestions you might have and I will consider them for future releases.
<h4>CSS3 Transitions UX Theory</h4>
Because of the way our brains process images, in simple terms, instant/sudden changes are generally not as well perceived as more gradual ones. In the physical space, we never see instant changes, like slides changing with no animation in a PowerPoint, but with digital technology this is a very common practice. When websites make use of hover states, for example, if a link changes color when the mouse hovers over it, they exhibit small, but instant visual changes. Adding the css3 transitions makes these changes more gradual, and therefore easier on the eye. For this same reason, operating systems now tend to make use of a lot of animations. There’s a lot of neuroscience behind these concepts, but I’m not well versed in that. Basically, slight animations generally look better than instant changes. Some people will argue that things aren’t as “snappy” or seem slugish with transitions, but if that’s the case, it’s only a matter of adjusting the animation timing function and duration.

CSS3 Transitions

This plugin automatically adds CSS3 transitions to your website/blog and the WordPress admin. Links, etc. get animated transitions between their norma …

CSS3 Buttons vs CSS3 Transitions