Edit: thought getting this info would be simple, but as PHP is very dynamic with objects.. well anyways.
$file objects generated by file_scan_directory() look like this:

$file->filename

full path from drupal root

$file->basename

filename

$file->name

filename excluding extension

file_check_upload() also creates these fields:

$file->filepath

full path from drupal root?

$file->filemime

mimetype

$file->source

where did the file come from

do does even reach anywhere outside the function? Is there a better way to dump this information?

$node->taxonomy is an array of taxonomy objects, as returned by taxonomy_get_term. Here's an example term:

// Taxonomy term ID is the same number as the key in the $node->taxonomy array
$node->taxonomy[1234]->tid = 1234;
// Vocabulary ID
$node->taxonomy[1234]->vid = 7;
// Readable label for the term
$node->taxonomy[1234]->name = "term label";
// Longer description for the term
$node->taxonomy[1234]->description = "longer description";
// Weighting of the term, if they've been re-ordered from alphabetical
$node->taxonomy[1234]->weight = 0;

// More terms
$node->taxonomy[5678]->tid = 5678;
// ...

Each CCK field you add in the admin interface is represented on a node by a new attribute, invariably beginning "field_" e.g. $node->field_venue or $node->field_subtitle. These are numbered arrays, even if the field is single valued (it's a single-value array). Each CCK field array element is itself an array, with field names which typically match the columns in the database where the CCK data is stored.

// Text CCK field
$node->field_subtitle = array(
  0 => array(
    // Textual content stored in e.g. a field_subtitle_value column,
    // so this ends up in the array key "value"
    "value" => "This is the subtitle",
  ),
);

// Long-text CCK field includes a "format" term for HTML filtering
$node->field_summary = array(
  0 => array(
    "value" => "Some text with <strong>markup</strong> in it",
    // Format e.g. Full HTML or Filtered HTML stored by numeric ID
    "format" => 1
  ),
);

// Node reference CCK field
$node->field_venue = array(
  0 => array(
    // Node ID stored in e.g. a field_venue_nid column,
    // so this ends up in the array key "nid"
    "nid" => 123,
  ),
);

// Multiple-value CCK field
// Node reference CCK field
$node->field_see_also = array(
  0 => array(
    "nid" => 123,
  ),
  1 => array(
    "nid" => 456,
  ),
  2 => array(
    "nid" => 789,
  ),
);

For the node path, if you have the path and pathauto module installed, you get a $node->path var.

This is the alias-ed path for you to check!

Thank you for posting this. Most handy page ever.

I had a problem: How to show the count (total) of Nodes on Faceted Search Guided Search.

Solution: Computed CCK field.

Approach:
1 - Created my Computed field and passed the: $node->language;
$node_field[0]['value'] = $node->language;

I hope this help somebody with the same problem in the future =D
enjoy

great post,i got it working afer some hours now
munka állás

If for any reason you want to hide 'Authored On' textfield from the node form, do not use

$form['author']['date']['#access'] = FALSE;

as this will remove the field from the form (obviously) and will make 'created' node property update together with 'changed' on each node save.
This behaviour comes from node_submit() line:

$node->created = !empty($node->date) ? strtotime($node->date) : REQUEST_TIME;

So, instead use the following code to hide the 'Authored On' field:

$form['author']['date']['#type'] = 'hidden';