Hitman Pro
Well I did a search and didn't see this one being discussed yet.
Hitman Pro is an anti-spyware program which automatically downloads and runs a few popular other anti-spyware programs such as spybot, ad-aware etc. It's basically just an AutoIT script and a folder for the programs.
I've copied it over to my thumbdrive and it works 99% already, but I think its writing to the registry so its not portable yet. I have to doublecheck the setup prior to running it on a new machine still. I'd rather set it up once, have the file on my thumbdrive and never have to worry about it again.
I saw in some other posts that its best if the software in question is open source, which this is not. It's freeware however and the author makes himself available, how does one go about getting permission? Is there a standard thing to ask?