Oil
Needless to say money an oil, in today's crude driven world, goes hand in hand.
The BTC pipeline carries crude oil from the Caspian Sea to the Mediterranean Sea. It connects Azerbaijan, Georgia and the Ceyhan port. I am short on time so won't go through two much detail but strategically speaking Russia would love to control this major crude pipeline as well as the South Caucasus Gas Pipeline running parallel to it. Simple enough goal the implementation of this plan is, of course, a diplomatic tight rope. There would be nothing better for Russia than to have a pro-Kremlin leadership which may be why their public policy seems to be shifting towards regime change as Mikhail Saakashvili is far to pro-western (what with his daily CNN interviews and all).

Power
NATO has shown a willingness to have Georgia to be a new member of the alliance but of course Georgia is of little help to NATO without a real army able to defend and protect the member states of the alliance. As a result Georgia has been building up its military as a prerequisite to its acceptance into NATO. Needless to say Russia views this in the context of the so called "Red" revolution and the "Orange" revolution (Political coups orchestrated by Washington, as far as Russia is concerned) and sees the membership of a border state as another way to surround Russia with enemies (similar to the scheme vise a vie Iran). For those familiar with the tenants of NATO it is clear that this type of action by Russia after Georgia was an official member would bring about the full weight of NATO forces (which essentially means Military conflict with the United States) and no one wants that. By taken action now they give both the Europeans and the United States an out, a reason not to intervene (I'm sure the Western powers are grateful). Military action against a neighboring state will give NATO pause when discussing missile defense with Poland, Ukraine and the like (which was one of the major sticking points with the Bush administration).

All in all I would score this a win for Russia as they have shown that they are not against escalation if the right buttons are pushed. This forces the Western powers not to push as many buttons as they have been over the past 4-6 years. As with Ukraine, Russia has an opposition to work with in Georgia. It will be interesting to see whether or not they have more political capital after the invasion.

One benefit that may play out for the United States is more support at home for the Missile Defense System Bush has been pushing for 8 years. Fortunately or unfortunately though, I highly doubt Bush has enough political capital left on the home front to get anything done. Furthermore, the host countries may listen a little more closely when Russia warns against it