diff -duar old/user.module new/user.module
--- old/user.module	2009-02-25 14:57:04.000000000 +0100
+++ new/user.module	2009-03-26 00:39:50.000000000 +0100
@@ -138,19 +138,73 @@
  *   A fully-loaded $user object upon successful user load or FALSE if user
  *   cannot be loaded.
  */
-function user_load($array = array()) {
+function user_load($conditions = array(), $reset = NULL) {
+  static $cache;
   // Dynamically compose a SQL query:
   $query = array();
   $params = array();
 
-  if (is_numeric($array)) {
-    $array = array('uid' => $array);
+  // Instantiate cache or reset cache when conditions are zero.
+  if (!$cache || (empty($conditions) && $reset)) {
+    $cache = array();
+    $cache['users'] = $cache['conditions'] = array();
+
+    if (empty($conditions)) {
+      return FALSE;
+    }
   }
-  elseif (!is_array($array)) {
+
+  // Make sure $conditions is an array at all times or return FALSE.
+  if (is_numeric($conditions)) {
+    $conditions = array('uid' => $conditions);
+  }
+  elseif (!is_array($conditions)) {
     return FALSE;
   }
 
-  foreach ($array as $key => $value) {
+  // Return user from cache if only uid was given.
+  if (isset($conditions['uid']) && (count($conditions)==1) && !$reset) {
+    $uid = $conditions['uid'];
+    if (isset($cache['users'][$uid])) {
+      return $cache['users'][$uid];
+    }
+  }
+
+  // Try to match the exact condition set and return from cache.
+  $uid_matches = array();
+  foreach ($conditions as $key => $value) {
+    if ($key == 'uid') continue;
+    if (isset($cache['conditions'][$key], $cache['conditions'][$key][$value])) {
+
+      // Collect the matching uid's.
+      foreach ($cache['conditions'][$key][$value] as $uid) {
+        $uid_matches[] = (int)$uid;
+      }
+    }
+    else {
+      break;
+    }
+  }
+
+  if ($match_count = count($uid_matches)) {
+    if ((array_sum($uid_matches) / $match_count) == $uid_matches[0]) { // Are all uid's in the array equal?
+      $uid = $uid_matches[0];
+
+      if (isset($cache['users'][$uid])) {
+        if ($reset) {
+          unset($cache['users'][$uid]);
+        }
+        else {
+          return $cache['users'][$uid];
+        }
+      }
+    }
+  }
+
+  // Dynamically compose a SQL query.
+  $query = $params = array();
+
+  foreach ($conditions as $key => $value) {
     if ($key == 'uid' || $key == 'status') {
       $query[] = "$key = %d";
       $params[] = $value;
@@ -164,10 +218,10 @@
       $params[] = $value;
     }
   }
-  $result = db_query('SELECT * FROM {users} u WHERE '. implode(' AND ', $query), $params);
-
-  if ($user = db_fetch_object($result)) {
-    $user = drupal_unpack($user);
+  $result = db_fetch_object(db_query('SELECT * FROM {users} u WHERE ' . implode(' AND ', $query), $params));
+ 
+  if (isset($result->uid)) {
+    $user = drupal_unpack($result);
 
     $user->roles = array();
     if ($user->uid) {
@@ -180,9 +234,30 @@
     while ($role = db_fetch_object($result)) {
       $user->roles[$role->rid] = $role->name;
     }
-    user_module_invoke('load', $array, $user);
+    user_module_invoke('load', $conditions, $user);
+
+    // Save the uid of the object in the conditions cache,
+    // we group the database keys, then their values so we
+    // have a unique match at all times.
+    foreach ($conditions as $key => $value) {
+      if (!isset($cache['conditions'][$key][$value])) {
+        $cache['conditions'][$key][$value] = array();
+      }
+      if (!in_array($user->uid, $cache['conditions'][$key][$value])) {
+        $cache['conditions'][$key][$value][] = $user->uid;
+      }
+    }
+
+    // Save user object in cache.
+    $cache['users'][$user->uid] = $user;
   }
   else {
+    if (isset($conditions['uid'])) {
+      $uid = $conditions['uid'];
+      if (isset($cache['users'][$uid])) {
+        unset($cache['users'][$uid]);
+      }
+    }
     $user = FALSE;
   }
 
@@ -276,7 +351,7 @@
     }
 
     // Refresh user object.
-    $user = user_load(array('uid' => $account->uid));
+    $user = user_load(array('uid' => $account->uid), TRUE);
 
     // Send emails after we have the new user object.
     if (isset($array['status']) && $array['status'] != $account->status) {
@@ -333,7 +408,7 @@
 
     // Build the initial user object.
     $array['uid'] = db_last_insert_id('users', 'uid');
-    $user = user_load(array('uid' => $array['uid']));
+    $user = user_load(array('uid' => $array['uid']), TRUE);
 
     user_module_invoke('insert', $array, $user, $category);
 
@@ -1596,6 +1671,7 @@
   db_query('DELETE FROM {users} WHERE uid = %d', $uid);
   db_query('DELETE FROM {users_roles} WHERE uid = %d', $uid);
   db_query('DELETE FROM {authmap} WHERE uid = %d', $uid);
+  user_load($uid, TRUE); // Update user_load()'s cache.
   $variables = array('%name' => $account->name, '%email' => '<'. $account->mail .'>');
   watchdog('user', 'Deleted user: %name %email.', $variables, WATCHDOG_NOTICE);
   module_invoke_all('user', 'delete', $edit, $account);
@@ -2254,6 +2330,7 @@
     $uid = $user->uid;
   }
   db_query("UPDATE {users} SET status = 0 WHERE uid = %d", $uid);
+  user_load((int)$uid, TRUE); // Refresh user_load()'s static cache.
   sess_destroy_uid($uid);
   watchdog('action', 'Blocked user %name.', array('%name' => check_plain($user->name)));
 }