Where to put Smarty, Styles, Scripts, etc?

[eluser]CodeIgniterNewbie[/eluser]
I need some advice on where to put the following directories:

- styles (for all my CSS stuff)
- scripts (for all my JS stuff)
- images (for all my image resources)
- Smarty library

I think styles, scripts, and images should be at the same level as my CI /system/ folder. So:

/images/
/scripts/
/styles/
/system/
/system/application/
/system/cache/
...

Is the above a good idea?

I'm not sure about where to put Smarty library, cache folder, etc.

Any assistance is appreciated. Thanks.