MacBook Upgrade Opinion?

I have a White, Late 2006 Macbook Core Duo notebook. It has a 2.0Ghz CPU, 1GB of RAM, and 60GB of HDD. And, I need a new battery.

I am thinking of purchasing a new battery, and installing the maximum RAM and HDD it can accept.

Here are my questions for the collective:

1) Battery: Would you purchase an Apple Battery? Or, would you prefer a 3rd party battery that may be cheaper and last longer (because of greater capacity).

2) RAM: I am getting conflicting information about RAM. Crucial, OWC, and NewEgg say that this system can accept only 2GB of 200 Pin, DDR2–667, PC2–5300 SODIMMs. However, several blogs report that they have made 4GB work successfully. Which source would you trust? Which memory would you purchase?

3) Hard Drive: There are bunch of Hard Drive manufacturers, speeds, and capacities. Do you have one that you recommend over others? I haven’t really kept up with hard drive manufacturers so I don’t know which model will run cooler, be less susceptible to failures, etc.

Thank you so much for your help!