The Oracle Database installation and interfaces (sqlplus like) have improved heaps from what I can remember from the days of 8i version. With Oracle XE, installation is so simple that even a pre-teen can do it. But still you cud hit stumbles like following one(s) and takes bit of googling for find you way out.
1. Unable to access Apex (formerly HTMLDB) application remotely.
The apex service by default (as on 10g) will be running at port 8080 and is accessible locally using http://localhost:8080/apex; but due to security-by-default policy it is not accessible remotely using http://myhost.mydomain:8080/apex. To enable it login, using sqlplus or sqldeveloper as sysdba and execute the following.
More hiccups to follow as and when encountered.