>> Tell me, how is the "Direct" option different from the Straight?
Direct is much the same as Straight, but they turn off more circuits; the idea being to influence the signal path even less.
'Straight' mans that the receiver is passing the signal directly though. So if it was recorded as surround you'll get surround; if it was recorded as stereo you'll get stereo. I've found Straight to be "less interesting" in most cases.
Yamaha has some nice sounds programs, you should give...