I don think using l33t adds much entropy to your password.
Since you take an interest to passwords, I’m also sure you’ve seen this comic by XKCD: http://xkcd.com/936/
It contains some good hints that may be helpful (as a simple variant of Diceware)

Also, use an encrypting password safe wherever possible. I don’t even know most of my passwords and I don’t miss them

It measures password entropy based on dictionary/bruteforce attacks.

Using this tool you can see that the entropy of “SoftLayer Private Clouds, no assembly required.” is about 120 and “S0L@Y#Rpr!Vcl0udN)#mblyR#Q” is 124 although “SoftLayer Private Clouds, no assembly required.” is much easier to remember.

Even if we lower the original password length to 26 characters and have “SoftLayer Private Clouds, ” because of the methods of brute force attack algorithms the password will take centuries to break. For an even stronger password it’s best if the words are unrelated (thus “SoftLayer Private Clouds” would most likely not be a good password to have on your SoftLayer server).

The key to remember is that each application / device should have its own unique password.