When I was younger I had a Countach poster but never one of a Ferrari, but if I had to use the money on one or the other it would have to be Ferrari.
I love the way the Gallardo looks and sounds (though interior disappoints) but not only does Ferrari have the great racing pedigree (F1 among others) but IMO nothing compares to the looks and sound of a 550/575 Maranello and that V12 or the 360 Modena and it's V8.
If it had to be brand new it would be a tougher decision (but still Ferrari) b/c I don't find the F430 or 599 to be as appealing.