Single layer 2 channel v. multichannel v. hybrid?

I have purchased a 2 channel SACD player (Sony SCD-1). In shopping for new music, I am wondering if I should buy only single layer 2 channel SACD's. Are there any compromises whatsoever in the other formats? Does the presence of another layer (either multichannel SACD or redbook CD) on the disc affect playback at all?
It would be nice to play my new SACD's on my crappy car stereo, or on my crappy Bose Wave radio (is it okay to say Bose on this forum?), but I would easily give up that ability and buy SACD only if I thought that there was a sonic benefit to doing so.
Seems like if I buy 2 channel SACD only, I can only play them on the Sony. I'm okay with that. If I buy hybrid, I can play them in the car or on the Bose, also. I'm okay with that, but I would not want to buy that ability at the expense of reduced quality on the Sony. If I buy multichannel, I have no idea what I would do with one of those. Play it on my friend's XA777ES?