I managed to let spyder use the virtualenv that I created (including pip install numpy/scipy/matplotlib/sip).
import matplotlib.pyplot as plt
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/mt/.virtualenvs/def2/lib/python2.7/site-packages/matplotlib/pyplot.py", line 98, in <module>
_backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
File "/Users/mt/.virtualenvs/def2/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 25, in pylab_setup
globals(),locals(),[backend_name])
File "/Users/mt/.virtualenvs/def2/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py", line 13, in <module>
from backend_qt4 import QtCore, QtGui, FigureManagerQT, FigureCanvasQT,\
File "/Users/mt/.virtualenvs/def2/lib/python2.7/site-packages/matplotlib/backends/backend_qt4.py", line 25, in <module>
from qt4_compat import QtCore, QtGui, _getSaveFileName, __version__
File "/Users/mt/.virtualenvs/def2/lib/python2.7/site-packages/matplotlib/backends/qt4_compat.py", line 36, in <module>
import sip
ImportError: No module named sip