A selection of last-minute upgrade questions!

I currently have a 2.33 GHz MBP with 120GB @ 5400rpm and 2GB RAM.
I'm looking to increase my RAM and HD size & speed. Here are my questions:

1. Crucial says my MBP can take a maximum of 3GB RAM so do I just need to buy a 2GB stick to replace one of the 1GB ones or do I need to buy the full 3GB to make sure everything is compatible? Also, is this upgrade worth it?

2. I'm considering upgrading the HD to the Hitachi 200GB 7200rpm drive for about £85 but ideally I'd like more storage but at 7200rpm... does anyone know if anyone is bringing out a larger capacity 7200rpm drive in the near future?

3. I'm using Tiger and don't want to upgrade to Leopard because certain music applications don't appear to run as smoothly. What's the best way to transfer everything (including applications) from the old HD to the new one? Can I just put the old HD in a caddy and transfer across or do I need to use some software first?

4. Will my iTunes playlists and ratings still exist when I transfer the data?

Thanks for any help!

 

Thanks for the reply, looks like Hitachi are releasing the Travelstar 7K320 at the end of the month so I'll wait for that!