Looking to upgrade to a socket AM2+ board, the Athlon 64 X2 6000+ (3.1 GHZ), Corsair Dual Channel Ram (2GB a piece), and a Radeon HD 3870X2 video card....I was wondering if my power supply would suffice. It's a Antec Neo HE 550 Watt PSU...Do I need to get more wattage or what??
Well your power supply might work, as it is the minimum amount needed according to ATI.
Might I suggest though that you get a 4870 or 4850 instead. You power supply would work perfectly for either of those cards and the 4870 is better than the 3870x2. In addition you don't have to worry about "dual gpu card" problems like scaling and microstutter which you would encounter on the 3870x2.
Normally I would say you would probably be okay providing you have a low energy system that doesn't use a large amount of power. User comments often indicate the 3870x2 video cards run hot and use a lot of power. There have also been user comments at vendor web sites and this forum indicating a top quality 500 watt psu could handle your type of system.