A few SQL queries are worth a thousands words:

mysql> SELECT VERSION();
+----------------+
| VERSION()      |
+----------------+
| 5.5.6-rc-debug |
+----------------+

mysql> SELECT @@global.storage_engine;
+-------------------------+
| @@global.storage_engine |
+-------------------------+
| InnoDB                  |
+-------------------------+

(Note: the above is without using the default storage engine option)

Scary! Excitement! MySQL!