If the outside counsel budget is your responsibility, currency fluctuations can hurt or help you. If your budget is denominated in dollars, for example, when the greenback falls, your fees paid to Euro-based firms climb. At least US firms negate currency fluctuations.
Aside from the swings in budgets, foreign currency payments throw other wrenches into the gears (See my post of Sept. 5, 2005: currency conversion for invoices from international firms; July 17, 2005: currency complications and VAT; April 9, 2006: alliance of software vendor and first user to iron out the kinks; April 22, 2007: tangle of currency conversion; Nov. 5, 2007: current thinking on currency conversion; and May 11, 2008: conversion issues when you reconcile matter management system to accounts payable.).
A related idea is purchase power parity (See my post of July 25, 2007: PPP with three posts cited.) where a general counsel attempts to pay people equitably after allowing for costs of living in different countries.