Low Power Consumption Graphics Cards

I have browsed on Internet which video cards are the most environment friendly. These are the less power consuption video cards which are fast (first number is the power consumption in watts, the second number is a benchmark number):

• ATI HD 5550     45W 612
• Geforce GT430  56W 697
• ATI HD 5570     43W 761
• ATI HD 7750     55W 1500

Nowadays I think if you use your computer for office work then 300 point is enough, if you are a gamer 1000 point is enough.