Two important questions are 1) how important is sound quality for that 10% of music and 2) what speakers are you using and how hard are they to drive?
I'm guessing music will be more of a secondary thing and so sound quality not of the utmost importance although you obviously want it to at least sound good. And if the speakers aren't a particularly hard load and considering you're listening at relatively low levels in a relatively small room with a sub it doesn't sound like you'll need all that much power. I'd go for something like a Yamaha RXV375 ($250 or less new), which probably has enough power for your needs and gets decent reviews for sound quality versus other receivers in the price range. The biggest remaining question would be if it has all the features/connections you need or want. Given what you described I think getting a separate amp/prepro might be a bit overkill for this situation. Hope this helps and best of luck.
I'm guessing music will be more of a secondary thing and so sound quality not of the utmost importance although you obviously want it to at least sound good. And if the speakers aren't a particularly hard load and considering you're listening at relatively low levels in a relatively small room with a sub it doesn't sound like you'll need all that much power. I'd go for something like a Yamaha RXV375 ($250 or less new), which probably has enough power for your needs and gets decent reviews for sound quality versus other receivers in the price range. The biggest remaining question would be if it has all the features/connections you need or want. Given what you described I think getting a separate amp/prepro might be a bit overkill for this situation. Hope this helps and best of luck.