External Hard drives
Whatever new external hard drive you get, make sure you format it as FAT32 so you can use it on both mac and windows. You never know when you need it
Recently i had to use my hard drive to backup my playstation 3, thank god i made it FAT32
Touch Pad
As soon as i got my mac, i went to preferences and enabled one finger tapping, two finger secondary click etc..it's so much better!
i remember when i first got my mac i never knew about it and was constantly holding down CTRL and clicking!
Spaces
I don't know how many people use Spaces, but i really love it. Soon as got my mac, i set up spaces allocating my emails to a different desktop, my microsoft word to another, safari to another one and so forth..made my life more efficient and easier. No more clouding of windows and minimising mania
Regarding Snow leopard- i would suggest upgrading straight away, even through there aren't any drastic changes from first glance, it's better to get used to snow leopard...more efficient and faster, certain subtle things like the new stash is much better
If you purchased your macbook from apple, it should come with snow leopard installed anyway, right?