Digital sound card for Bitstreaming to AV receiver instead of ATI 5450

So, I just finished building my new work/media center PC. I am currently using two ATI 5450s to drive two monitors and a HDTV (Samsung LED through Sony STR-DA 5300ES). The main reason I went with ATI 5XXX series is that they can do Bitstream over HDMI. All that worked good and surround sound in movies sounded great.

However, I have been having several issues with ATI video drivers and after 5 OS installations and several tweaks, I am officially giving up on ATI. So, I will be getting 2 NVIDIA cards soon to drive three displays. However, I will not have bitstream audio. The onboard realtek audio port can only do LPCM and that too, it does not do a good job of that (sometimes swaps the channels and sometime ignores them).

My question is, if I am willing to compromise on Dolby HD and DTS HD, is there is sound card (or a non ATI GPU) that can do all that ATI 5450 did (I do not want to compromise on bitstreaming) (My receiver can combine HDMI and optical so I am not worried about that aspect - in fact, I already have an optical cable running to AVR).

Any help is appreciated.

Core i7 920
Gigabyte X58-UD5
2XGigabyte ATI HD 5450 (soon to be returned)
3X2GB OCZ OCZ3G1600LV6GK DDR3 1600MHz
Thermaltake 850W
Arctic Freezer Pro Rev.2 Cooler
Antec 900 2 Case