Newbie needs assistance with solar powered sculpture

Hello, I've searched previous postings and have gathered tidbits of information, but I am hoping there is someone on this forum with the cumulative experience to provide guidance for a new project.

The project: A solar powered interactive sculpture that includes a motion sensor, LEDs, MP3 player/speakers, and camera. The motion sensor will trip the camera, which will record photos on an SD card. The sensor will also trip a few LEDs and the MP3 player. The LEDs will light up at dusk for an hour only, and when the sensor is tripped (rarely, since the sculpture will be placed in a remote locale). So, not a whole lot of energy usage. It will be powered by a lead-acid battery and 10watt solar panel, with a charge controller to avoid over-charging and panel discharge.

The questions: 1) 6volt vs. 12volt battery. I've seen arguments in favor of both on this and other forums. I don't believe my power requirements are high (90db speakers, camera (JPEG Trigger with LinkSprite JPEG Color Camera), and MP3 player (Wave Shield?) once in a while, and a few LEDs for about an hour while everyday). 2) What speakers to use? I'm assuming they will need to be powered directly from the battery. What about amplification? 3) Voltage regulator? 4) Any circuit diagrams for similar projects someone could share?

Thanks in advance!