Which remote logging will be more useful?

I have difficult choice. What kind of remote logging should be implemented first.

At present moment we have:

• File-based remote logging (ftp, sftp, dav, ...)
  
• Database remote logging (MySQL, SQLite, PostgreSQL, ...)
  
• XMPP remote logging or Google Talk based remote logging.
  

The last choice was preferable for me early, but after discussion with my mentor Richard Laager, this variant is not seems so good as before because:

• We don't know how exactly GTalk implements XEP-0136.
  
• It may be incompatible with other XMPP servers later.
  
• I don't know other XMPP servers which implement XEP-0136.
  

So, as Richard said that "database logging is still a really common request" I think this way is really good decision.