A few comments here. This article reinforces that watts from an avr do not equal watts from a good two channel amp. A 40wpc 2 channel can dig deep, depending on its design and it sounds like the Rotel a10 can. It’s hard to get without really listening to but I’m glad that you’re open to the idea!
Second, the a10 doesn’t look like it has a remote control, so using that for a dual music/movie/tv setup could become annoying. Also, the 40wpc might be plenty for music but you might consider moving up the line to the a12 or a14 to dig a little deeper for movies. Loud scenes in movies can use substantially more power for longer periods of time than loud parts of a song. The amps look like they’ve been redesigned and I haven’t heard them with the ls50s so that would be a blind recommendation, but if the predecessor sounded good with them, it’s a fairly safe bet that the new ones might.
Third, these don’t appear to have home theatre bypass, which I think isn’t a big deal. Just keep in mind that when you want to eventually go to a surround setup, it will require replacing the Rotel. I’m sure it will keep some resale value, they are quality components. To be honest, I think you should choose a 2 channel amp that fits your budget and you’ll be happy with without the HTB input because it will limit you. At this price point, there just arnt many options for integrated amps with HTB.
Fourth, the Rotel a10 doesn’t have any digital inputs, which is why the reviewer recommended a separate DAC (Digital to Analogue Converter) for digital sources. Some DACs have multiple inputs that you can switch between for TV and PC. The newer a12/a14 have been redesigned with internal DAC’s so there may be more different with these units than I thought. Just try and find some online reviews, or even better find a dealer to try and demo the amp. That might be hard out of context for you since this seems like you’re first stab at building a system but the best resource is hearing something for yourself. That’s generally why companies offer in home trials for varrrying amounts of time. I started with integrated with internal DAC’s and it’s a fine way to go. It gives less flexibility in terms of upgrading that in the future but you could always just buy an external DAC and feed it into an analogue source in the Rotel to bypass the internal DAC.
Happy hunting!