PHP: What's a better way to process form data?
function update_account() {
    global $current_user; get_currentuserinfo();
    require_once( ABSPATH . WPINC . '/registration.php' );

    $uid = $current_user->ID;

    // First Name
    if(isset($_POST['first_name']) && $_POST['first_name'] <> $current_user->first_name) {
        wp_update_user( array(
            'ID' => $uid, 'first_name' => esc_attr($_POST['first_name'])
        ));
    }

    // ...and so on 43 more times...

}

// All the fields you wish to process are in this array
$fields = array('first_name', 'last_name', 'others',...'others99');

// Loop over the array and process each field with the same block
foreach ($fields as $field) {
    if(isset($_POST[$field]) && $_POST[$field] != $current_user->{$field}) {
        wp_update_user( array(
            'ID' => $uid, $field => esc_attr($_POST[$field])
        ));
    }
}

function update_account()
{
    // initialize a new form class
    $form = new UserAccountInfoForm();
    // give the form to your view for rendering
    $this->view->form = $form;
    // check if form was posted [however your framework provides this check]
    if(!Is_Post())
        return $this->render('accountform.phtml');
    // check if posted form data validates
    if(!$form->isValid($_POST))
    {
         // if the form didn't validate re-display the form
         // the view takes care of displaying errors, with the help of its
         // copy of the $form object
         return $this->render('accountform.phtml');
    }

    // form validated, so we can use the supplied values and update the db
    $values = $form->getValues(); // returns an array of ['fieldname'=>'value']
    // escape the values of the array
    EscapeArrayValues($values);
    // update db
    wp_update_user($values);
    // inform the user of successful update via flash message
    $this->flashMessage('Successfully updated profile');
    // go back to main profile page
    $this->redirect('/profile');

<form action='post'>
<label>first name</label> <input class='<?=$this->form->getElement('first_name')->hasError() ? "invalid":""?>' type='text' name='first_name' value="<?=$this->form->getElement('first_name')->getValue()"/> <span class='errmsg'><?=$this->form->getElement('first_name')->getError()?></span><br/>

<label>last name</label> <input class='<?=$this->form->getElement('last_name')->hasError() ? "invalid":""?>' type='text' name='last_name' value="<?=$this->form->getElement('last_name')->getValue()"/> <span class='errmsg'><?=$this->form->getElement('last_name')->getError()?></span><br/>

<label>other</label> <input class='<?=$this->form->getElement('other')->hasError() ? "invalid":""?>' type='text' name='other' value="<?=$this->form->getElement('other')->getValue()"/> <span class='errmsg'><?=$this->form->getElement('other')->getError()?></span><br/>

<input type='submit' value='submit'/>
</form>