Recently discovered there are interesting new entries within my loved portable apps:

1. Skype, never thought it could ever go portable.
2. TeamViewer, one of my favorite collaboration and remote support tools. Really powerful, give it a try.
3. 2X Client, RDP remote client with interesting features.
4. Google Chrome (beta 4), personally I found that a portable browser is a must.

For the complete list of portable apps give a look here. Notice that almost everything is free.