I'd say Pound > Euro > Yen > Dollar .
European currencies are the most stable - time has shown.
I remember when Dollar and Euro were head to head. Actually - I love this when dollar is weak - less euro per month for hosting bills :)
Back from sysadmins to the programmers.
I'm from England but I'd say that the Dollar has most value People all over the world trust the value of a dollar - heck, in many countries they'd rather have dollars than their own currency - can't say that about the Pound, Yen or Euro
The dollar is deflating, it has been for a while. If you are looking to invest in something I would try another currency. Although many have hope for the dollar because its crashing means the world market will follow.