Installing Linux, specifically Mint, for first time...

[exploder]

I am not sure about your partitioning question, you have a lot of space! I know ext3 would probably be best for your file system. With so much space I would just let Mint automatically set up the partitions.

As long as no one knows your password they can not install anything. I have just one account on my machine and it is set to auto log, so anyone can use my pc. Only I know the password. My Wife and Kids can use my pc if one of the others is in use and I do not have to worry about anything getting messed up too bad.

I try and keep things simple, someone else may have another idea.