Halal (meaning lawful) meat is meat that is slaughtered in permissible means by Muslims. It is a recommendation to make sure that your meat is Halal. It is also important to take note of what animals are permissible and not permissble to slaughter and eat.
Eating Halal meat is a better choice than eating non-halal meat, as it is slaughtered according to Islamic law. Halal meat is also usually a pure type of meat that is free from harmful substances.
It is also believed that Halal meat tastes better than non-halal meat, and that it usually stays fresh for a longer period of time. Non-halal meat may contain substances not healthy for the body, such as containing blood.
The Qur'an states about Halal meat:
"Made lawful to you this day are At-Tayyibat [all kinds of Halal (lawful) foods, which Allah has made lawful (meat of slaughtered eatable animals, milk products, fats, vegetables and fruits)]. The food of the people of the Scripture (Jews and Christians) is lawful to you and yours is lawful to them." (1)
Meats such as pork are not permissible to eat, and meats that have been slaughtered as sacrifice to others than Allah. Meats permissbile to eat are meats of Ahlul-Kitab (People of the Book), beef, lamb, goat, chicken, etc.
The Qur'an says about this:
"Forbidden to you (for food) are: Al-Maitah (the dead animals - cattle - beast not slaughtered), blood, the flesh of swine, and that on which Allah's Name has not been mentioned while slaughtering, and that which has been killed by strangling, or by a violent blow, or by a headlong fall, or by the goring of horns - and that which has been (partly) eaten by a wilf animal - unless you are able to slaughter it (before its death) - and that which is sacrificed (slaughtered) on An-Nusub (stone altars)." (2)
Another reason for meats to be permissible to eat is that they must be slaughtered correctly. The slaughterman must be a Muslim, or from Ahlul-Kitab, and slaughtered using a sharp blade that does the least amount of pain. The slaughtered animal must be a halal animal, such as cows, chicken, goat, etc. Also, the name of Allah (subhanahu wa ta'ala) must be mentioned, by saying Bismillah at the time of slaughtering.
All of these requirements must be fulfilled for the meat to be considered Halal. If not, than it is not considered Halal meat.
To sum it up, Halal meat is the correct meat to eat, but for it to be considered Halal, it must be slaughtered according to Islamic law.
May Allah bless you, and shukran.
1. Qurʾān 5:5
2. Qurʾān 5:3