Graphics Card: decisions decisions...

Hello all, I'm in the market for a new graphics card as the ol' Nvidia 6200 is getting close to the end of its usefulness to me
. I am running FS9 as well as a bunch of other games on my computer. I have an HP m7160n, everything stock except for the video card and the memory. PCI-E bus.
I am looking to spend $200-300 CAN but feel free to mention $400 cards as sales are easy enough to find.
A few questions, Should the brand be a huge consideration for me (BFG as opposed to Asus), and should I be worrying about DX10 cards (I am not looking to install FSX or Vista anytime soon).
Any and all information is greatly appreciated!!
Thank you
Edit: The cards i've been eyeing are;
BFG 7950GT OC 512MB
BFG 8500GT 512MB
EVGA 8600 GTS SC 256MB

I am looking to spend $200-300 CAN but feel free to mention $400 cards as sales are easy enough to find.
A few questions, Should the brand be a huge consideration for me (BFG as opposed to Asus), and should I be worrying about DX10 cards (I am not looking to install FSX or Vista anytime soon).
Any and all information is greatly appreciated!!
Thank you

Edit: The cards i've been eyeing are;
BFG 7950GT OC 512MB
BFG 8500GT 512MB
EVGA 8600 GTS SC 256MB