Firefox -moz-border-radius doesn’t work on images unfortunately. Using -webkit-border-radius however works well on images in Safari and Chrome etc. A recent customer wanted images on there site to have rounded corners. They where ok with it not working in Internet Explorer 8 and older but really wanted a fix for Firefox.
The search field is an important part of almost any web site today and it deserve some attention. Especially if you have implemented some really good search like Apache Solr (see How to set up Apache Solr search for Drupal 6 on a Debian GNU/Linux server).