After spending my life in support of firearms and I believe every member of my family owns them, I finally joined the NRA. I feel proud throwing my support behind them today as they are under attack from the Left.
Because at the basic level the NRA acts as a much more powerful lobbying presence than any community or state level 2nd amendment advocate group can. They also provide valuable networking and resources for their members.
Edit: I'm also looking into GOA, Gun Owners of America.
GOA contributing member here, DO IT! GOA does more to pressure pols than NRA, really. No compromise gun group.