PSU advice

I'm fully upgrading my desktop computer next week, and it looks like I need a new power supply. (The one I have is 450W only and is completely unreliable).

Here is the list of components:

Mobo: Asus P8P67 PRO

CPU: Intel Core i7-2600

GPU: MSI N560GTX-Ti Twin Frozr II

RAM: Corsair 1333 MHz 8GB (2x4GB)

HDD: Western Digital (2x 500GB)

2 PCI cards (Creative Sound Blaster Audigy and D-Link 802.11 b/g/n WLAN)


What do you guys think? Will 550W be enough for that setup? Also, I'm planning to add a second GTX560 Ti in a year and upgrade to Sound Blaster X-Fi Titanium (with the front I/O drive), what PSU would I need then? And what brand should I go for, Antec or Huntkey? (These are the only two brands easily available in my area.)

Thanks in advance.