Are there any Hadith/Quran citations that refer to celebrating an individual's birthday?
Is birthday celebration allowed? If yes, what is and is not appropriate? What other basic rulings are relevant for planning one?
There's a difference between scholars; many scholars say that celebrating birthday is haram. Here's the fatwa in Arabic.
But there are many trusted scholars who disagree and says it's halal and you can celebrate birthday unless it involves haram acts, like drinking beer or so, in which case it's haram.
You can survey the birthday celebration from two different angles.
You can survey and look at this (birthday celebration) as just a celebration which is not relevant to the islam as an islamic celebration, thus in that case it doesn't appear to be haram. But you can survey the matter of birthday celebration somehow as if it is relevant to islam, hence in that case it can be counted as a bid'ah. And as possibly you are aware, bid'ah is one of haram things from the view of Islam.
“Then We have put you (O Muhammad) on a plain way of (Our) commandment. So follow that, and follow not the desires of those who know not. Verily, they can avail you nothing against Allaah (if He wants to puish you). Verily, the zaalimoon (wrongdoers) are awliyaa’ (protectors, helpers, etc.) to one another, but Allaah is the Wali (Protector, Helper) of the muttaqoon (pious).” [al-Jaathiyah 45:18-19]
Full fatwa here: http://islamqa.info/en/ref/1027
Celebrating birth dates is derived from pagan beliefs:
“For thousands of years people all over the world have thought of a birthday as a very special day. Long ago, people believed that on a birthday a person could be helped by good spirits, or hurt by evil spirits. So, when a person had a birthday, friends and relatives gathered to protect him or her. And that's how birthday parties began.”
(The World Book -- Childcraft International)
Clearly, the birthday culture is derived from pagan religion and has no place in Islam. The belief behind this practice is far from Islam, if you practiced it due to ignorance, then you're not at fault, but when you have knowledge and continue to practice pagan rituals, then you're at fault and will be brought to account in the judgement day.