OK, I'll take the opposing view.
You are correct, some of your current equipment is is a different league. You already have some of the building blocks for an EXCELLENT music system. I think you would be better served if you continue to build on the music side (that is assuming that you are happy with your HT).
That said, here is what I would do:
Instead of buying a power amp for the fronts, I would buy a quality integrated amp that has an HT processor/bypass loop feature. I would connect the Arcam CD player and your turntable to the integrated amps inputs and connect the front L&R speakers (Hales) to the integrated amps outputs. INSTANT high-end 2-channel rig!! As you can see, this is now a dedicated 2-channel music system with zero possibilities of being "mucked up" by the mid-fi receiver.
For HT, you would connect the DVD player, VCR, etc., to the receiver as you are now doing. The Front L&R pre-outs from the receiver would go to the processor/bypass loop inputs on the integrated amp. When you select "bypass" on the integrated, it will work EXACTLY like your proposed power amp, "bypassing" any of the pre-amp controls of the integrated amp.
For me, this is an great way to have the best of both worlds. You have a dedicate 2-channel rig AND an add-on HT setup and they only share the Front L&R speakers and the "power-amp" portion of the integrated amp. I have put together several version of systems using this type of setup and they work very well. And, it eliminates any concerns of your mid-fi receiver "stangling" your amplifiers output.
Feel free to send me a message if you need any more details.