OK - I'll bite - but will pass you elsewhere - my only knowledge is places to go for you to get the right information.
There is much talk about the Pearl having variable brigtness over its focus range. This has something to do with the lens I believe. I think at the minimum you'll have the brightest image that the Pearl is capable of throwing, but at the sacrifice of the deepest blacks it's capable of. You'll find more information about this is some of the Pearl threads. In addition I'd point you to the widescreen review Pearl review - that can be found on their website. It's very very detailed and will give information about this.
Denon builds good stuff and the 1920 is a respectable transport. I'm not sure the only other option is to go and build a several thousand dollar HTPC though. The decision to build an HTPC is not just about DVD playback, but media storage, distribtion, etc...If you're looking for DVD only solution that might be a bit much. There are other upgrades that will pair nicely with the Pearl - for example - how about a HD-DVD player? You are moving to a 1080p display - how about a nice 1080p (or i for right now) source to pair with it. The Toshiba HD-DVD players offer very good upconverting (meaning you could replace your Denon) and will give you some really specatular source material to play on your new toy. I believe the 2nd generation units are bieng released in Europe right now. These are faster than the first gen, much more ergonomically statisfying and produce stunning results.