Using Two Decks Options

I have been working with cards for a little while now but, am not very experienced. The first deck I bought (and one I am more familiar with) is a deck of Fairie Oracle cards. Over the summer, I bought a Hermetic Tarot deck and have been working with it much more than I have the Oracle cards. This evening a friend and I had a discussion about using multiple decks in a reading. She was rather concerned over combining use of two very different decks of cards.
I was wondering whether it was a good idea to use these two types of cards in one reading and, if so, what sort of spread would be used?

I agree with Vagrant here - the best way to learn is to experiment with the decks. I would recommend though that you have that the two decks be attributed to two different aspects - perhaps using them in parallel in the same reading. For example, use one deck for your relationship with your dog and another for your practical external life. Do a parallel reading to examine the forces of nature involved between your relationship with your dog and determine how it affects your life.

Perhaps you may get some result, which tells you that you are not spending enough time with your dog so he is sad - and that the reason is that you are much to involved with your job or your cat. :-)

Of course you can make up your own methods and be creative - that in my opinion is a large portion of doing magick. Just be clear and consistent in your method and be sure to document your results.