Making Client inherit from Stream, which unforunately means taking peek() out of Stream for now, since there's no immediate implementation for Client.

build/shared/revisions.txt

@@ -23,8 +23,8 @@ ARDUINO 0019
 * Added Serial.peek() method.
   http://code.google.com/p/arduino/issues/detail?id=270
 
-* Added Stream base class to Serial object (w/ available(), peek(), read()
-  and the write(), print(), and println() functions from the Print class).
+* Added Stream base class to Serial object (w/ available(), read() and
+  the write(), print(), and println() functions from the Print class).
   http://code.google.com/p/arduino/issues/detail?id=60
 
 * Disabling interrupts while digitalWrite() and pinMode() write to pins.

hardware/arduino/cores/arduino/Stream.h

@@ -27,7 +27,6 @@ class Stream : public Print
 {
   public:
     virtual int available() = 0;
-    virtual int peek() = 0;
     virtual int read() = 0;
     virtual void flush() = 0;
 };

libraries/Ethernet/Client.h

@@ -3,7 +3,7 @@
 #include "WProgram.h"	
 #include "Print.h"
 
-class Client : public Print {
+class Client : public Stream {
 
 public:
   Client();
@@ -15,9 +15,9 @@ public:
   virtual void write(uint8_t);
   virtual void write(const char *str);
   virtual void write(const uint8_t *buf, size_t size);
-  int available();
-  int read();
-  void flush();
+  virtual int available();
+  virtual int read();
+  virtual void flush();
   void stop();
   uint8_t connected();
   uint8_t operator==(int);