I think before u start listing the best armies , u have to take into account the character of the mission , if it's power projection , undoubtedly the brits r #1 . But what happens after that , the Raf as of right now doesn't have enough to grasp air superiority over the ada , so their striking power don't matter . Even though british forces have shown their mobile nature nesseciated by a very mobile and aggrasive doctrine , the volume of troops deployed for operations in iraq and other areas given their extensive period of deployment and the large sealift ability is simply not good enough to tip the balance against the French or german land army who will have more volume and quality edge over the brits esp. France. And in the naval arena , RN is simply the best .
AF - French
army - german/french ( depending on the situation )
Navy - RN

But if there were a fight between these countries the sea would act as a 4th armed service for the brits making her immune to any invasion .