Buying in while things are on "sale" is a great idea. Since it sounds like you have no other investments in the stock market, however, I would strongly encourage you to choose an index fund as your first investment. The reasoning being, there is no guarantee that a given stock will respond favorably to a resolution of the fiscal cliff, as you are still subject to the vital signs of that particular company. The market as a whole, however, *will* rally after a fiscal cliff resolution, and will continue to grow ever upward over the long term.
SWTSX, VTSAX/VTSMX , etc. are excellent total stock market funds which allow you to own a broadly diversified "share" in the whole market. This means that unless the market itself disappears, your shares don't disappear. Plus, this is a strategy that is verifiably MMM-Approved (tm).