Help me decide antec or seasonic

Both PSU are fine at their price points. For your RIG the Seasonic PSU will suffice so go for that one.

Antec PSU will give you more headroom for upgrade since it has higher wattage.

These are the official recommended power requirements based on your graphics card:

450 Watt or greater power supply with 75 Watt 6-pin PCI Express® power connector recommended (550 Watt and two 6-pin connectors for ATI CrossFireX™ technology in dual mode)

This applies to the whole system not just your card.

Both brands have a very good reputation for consistently producing high quality PSUs. However as you can see from the above requirements, the 520W unit would be more than enough for your needs so that would be by recommendation.

Thanks. I am inclined towards the Antec simply for the higher Wattage for possible future requirements. I was hoping someone had direct experience with either of thesePSU.On the other hand I may never need the 650W

Not direct experience but you can more or less guarantee that they will be of high build quality from those two manufacturers. If you're worried you may require more than 520W or just want the scope for the future then go for the 650W. However, even if you do add that extra HDD and Blu-Ray Drive I wouldn't say you'd need more than 520W.

Hmmm.... which Antec model? Is it the older Antec True Power or the new and improved Antec True Power New?

The Antec True Power New is the better of the two Antec models.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Its the new antec true power

Then go for it!  

do you believe in rebate's?

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

obsidian86 - nice rebate!  

i noticed they usually have the tp 750 on special which drops the price below the tp 650's very often

if you wont need that much you can stick to the tp 650 or the corsair tx 650 which also has a nice rebate

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Quite often, I got mine for $96 no rebate involved.
There are also weeks when they have it listed at retail