Also, have you had experience with the two auto setups? The Denon offers the Audyssey multi-EQ whereas the Onkyo offers the slightly lower end Audyssey QE2. Would that make a difference in your mind?
If neither of those things would matter to a more experienced audiophile, than I guess I'll go with the Onkyo.
First of all, Im not terribly familiar with your choices. But, for me, the version of room correction is a very big factor.
IOW, stepping up to m-eq is worth it.
Even better would be m-eq XT.
OTOH, at price point you're looking at, hard to find XT coupled with Dyn vol/eq (useful for quiet volumes, late at night).
The 606 is feature heavy, but does not sport pre-outs, if you wanted to add an amp for future power-demanding speakers.
However, room correction doesn't excite everyone else as it does me. Its all personal. YMMV.
edit: ok after bit of reading, it seems the 1909 is the nicest choice of listed. preouts, handles advanced bitstreams unlike 2308, has dyn vol/eq, one more hdmi input. bit more expensive though.
edit #2: oops 1908 listed, not 1909. Ok, then, I vote 2308. I hope your bdp is not the Pana bd-30 that only bitstreams.