Ultimate boot CD for Windows in USB

Ultimate Boot CD for Windows is an indispensable tool when a system needs to be recovered. But when you have for instance a vírus on a computer, it's not easy to keep it up to date, because it runs on a CD that can only be updated when you write it. So it's much more flexible to have this tool on an USB pen, where I can write and update some files. There are some nice tools to make an ISO available on USB boot, I highly recommend these:
- WinSetupFromUSB - great but on Windows 7 x64 does not work well with UAC active, also supports install Windows from USB
- USB boot without BIOS support - this works great for me and can make a system boot even without USB boot support, by using an ISO that boots with USB support.

Additionally to this, I use Ketarin, a must have tool to keep virus definitions updated on the USB.