My config.rb preferences. Adjusted on a per project bases, this is just a good starting point for how I typically configure my Sass/Compass projects.

config.rb

# Require any additional compass plugins here:
# example:
# require "susy"

project_type = :stand_alone

# Set this to the root of your project when deployed:
http_path = "/"
sass_dir = "scss"
css_dir = "css"
images_dir = "img"
fonts_dir = "fonts"
javascripts_dir = "js"

# You can select your preferred output style here (can be overridden via the command line):
# output_style = :expanded or :nested or :compact or :compressed
output_style = :compressed

# To enable relative paths to assets via compass helper functions. Uncomment:
relative_assets = true

# To disable debugging comments that display the original location of your selectors. Uncomment:
line_comments = false

# To use my preferred scss syntax:
preferred_syntax = :scss
# If you prefer the indented syntax, you might want to regenerate this
# project again passing --syntax sass, or you can uncomment this:
# preferred_syntax = :sass
# and then run:
# sass-convert -R --from scss --to sass sass scss && rm -rf sass && mv scss sass

no-comments-config.rb

require "susy"

project_type = :stand_alone
http_path = "/"
sass_dir = "scss"
css_dir = "css"
images_dir = "img"
fonts_dir = "fonts"
javascripts_dir = "js"
output_style = :compressed
relative_assets = true
line_comments = false
preferred_syntax = :scss