I'm happy to be on a winning team. My individual success, that lasts for a short period of time. The success of being a part of the South, of Atlanta, which is now the hot bed of music, that's what's gonna last the longest. The fact that I contributed to planting our flag and moving music to my city, that's what I'm most proud of.

This quote means that the speaker is more proud of belonging to a winning team and contributing to the development of something larger than himself, rather than any individual accomplishments that may come with it. The speaker is particularly proud of being part of the South and of helping to bring music to Atlanta, or to “plant the flag” in the city. The speaker believes that this contribution will last longer than his individual successes and is something to be especially proud of.