Easy to bi-wire
It's very easy to bi-wire your speakers to the Denon 3805, assuming that your speakers are set up for bi wiring. This is not the same thing as bi-AMPING.
To bi-wire your speakers, they need to have separate terminals for the tweeters and midrange/lower-range drivers. From each speaker, you will then have two positive wires and two negative wires. Simply connect these to the positive and negative front speaker terminals on the 3805, with the four wires from the left speaker going to the Denon's left front speaker connectors, etc. I have KEF Q7's, and they were easy to connect this way using large-gauge zip cord. If you want to go fancy, it's not hard to find a set of bi-wired speaker cables that terminate in banana plugs on both ends.
Is it worthwhile? Some people claim to hear a difference with bi-wiring, while others say it makes no difference.