Like previously stated, it depends if you're a hot or cold sleeper, how much $ you have in your budget and shelter/pad combo. I am a cold sleeper. Over the last several seasons, I've found myself wearing base layers and down insulation to bed regularly in the CO alpine. This is paired with an older 15 degree synthetic and some drafts moving through the 3 season tent (wind always blows where I hunt). We got caught in a cold snap last year in September and we got hammered with snow/wind; I shivered all night wearing almost all my clothes in my bag. I'm probably more of an exception, not the rule.
I will be upgrading to a Rab 10 degree down bag this year, but still probably going to were base layers to bed. Hope this helps.