Change searchform.php line 5 from
PHP Code:
<input type="text" class="text inputblur" value="<?php the_search_query(); ?>" name="s" />
to
PHP Code:
<input type="text" class="text inputblur"
onfocus="this.value='<?php echo (get_search_query() ? get_search_query() : '' ); ?>'"
value="<?php echo (get_search_query() ? get_search_query() : 'DEFAULT SEARCH TEXT' ); ?>" name="s" />
Replace DEFAULT SEARCH TEXT with your default search text, i.e.
search