Windows 7: The Cure Trilogy Blu ray best audio settings?

Hi guys i have a doubt since long time ago.
I have a PC, two bose companion II speakers, a blu ray unit and an omega striker 7.1 audio card.

If i play a bluray i have this audio options:

1) LPCM Stereo, i've already known this if for a two speakers system.

2) Dolby Digital 5.1. Is this exclusively for 5.1 home theaters?



3) DTS HD Master Audio.

Which option should i select in order to have the best sound with my equipment?

I know maybe some of you are gonna say, well whichever you like, but which is the correct selection according to my system?

Thanks.

They're all lossless formats... Read the following:
Uncompressed LPCM track vs DTS HD MA track [Archive] - High Def Forum - Your High Definition Community & High Definition Resource

Thanks for answering, i don't get this:

DTS MA - Great DTS core soundtrack for those that dont have equipment for lossless audio

which equipment? a pc with two speakers? if yes, LPCM or DTS MA?