All,
I've been lurking in these forums over the past several months, and I was in the market for a HTIB. I've considered the Sony SF2300 although there is no where in my area where I could go and hear it, and the Denon DHT 588. Last week Circuit City had it on sale, and they had an online coupon to sweeten the deal. I went to CC to see and hear the system. It was hooked up in the middle of the store, so I had the salesperson turn down the volume on most of the TV's, and then listened to the 588. It really sounded great, so I purchased it with the thougth being that if I didn't like it at my house, I could just return it.
As others have said, you really need to read the manual, and yes, it probably could have been better written. However, after spending some quiet time reading the manual, I hooked up the system, and made some very minor tweaks.
Regarding the hook up, I connected my cable box and my Sony blue ray to the receiver with a digital coax cables. I initially tried digital optical cables, but for some reason, they didn't stay firmly attached to the equipment, and yes I did remove the little plastic covers. I actually bought 2 of the digital optical cables (~$100) from CC, and returned them. I went to Radio Shack and picked up 2 digital coax cables ($40). I still use a HDMI connection to my Sony 52W3000 for the cable box and the blue ray, with the thought being that I could still watch/listen to the TV without using the sound system.
Last night on a high definition channel, I watched most of Transformers with the sound system turned on, and all I could say was that the sound was truely amazing. I have the system in my basement, and I really didn't crank it up that much because my wife was upstairs watching Desperate Housewives, and besides that, it was mothers day.

Again, other than needing to take some quiet time to read the manual, I feel anyone would be really pleased with the system. The Boston speakers and powered sub really perform very well.
I would be interested in hearing any feedback from current owners of the Denon 488/588 systems, but after 2 days, I don't think I will be returning mine.