In the next picture you can see the circuit board a little closer. I'm using an LM317 with a couple resistors and capacitors to provide 3.3V for the MSP430, and then the LED strand is switched on my a 2n3904 transistor with a 1k resistor on the gate. Using the ez430 target board makes it easy to connect to the programmer/debugger, and it's not much more expensive than the bare chip (~$3.30 vs ~$2.70). One of the value line (MSP430G series) chips would certainly have worked, but I had a few of these target boards lying around and it did the job just fine.
Below you can see a video of the tree in action. The tree plays the full Star Wars Theme, but this is just the intro. It looks better in person than on my camera, but you at least can get the idea. My wife was kind enough to play violin along with the tree for the accompaniment. You can download the source code here if you want it.