Are you near a MicroCenter? I ask because they have great in-store pricing on CPU/motherboard combos. You can snag an i5-4690K and an ASRock board for almost the same price as that microATX/4590 non-K pairing you have there. Of course, the K just means you can overclock it, and I'm not sure that you'd care to with an HTPC (I've got a 4670K myself, never even thought about overclocking for real).
Some other notes I'd make:
RAM: Do you have some brand allegiance to Corsair? I don't see the reason to spend $88 for two individual 8-GB sticks, when you can get
something like this, where it's $75 for a pair of 8-GB sticks.
Storage: If you're primarily doing media, is a 240-GB SSD going to be enough on its own, or are you going to use a second drive you already have? There are also quite a few SSDs in the same storage range at lower prices, like the 250-GB
Samsung 850 EVO. It's basically the same price, but with many more reviews. There's also this
$72 Kingston, which is the same capacity and has solid reviews. I'm not too sure on which iteration of those drives it is, though some of the older ones allegedly had controller issues (granted, I have a Kingston with the supposedly bad controller, but mine's been 100% fine).
GPU: The video card's mostly going to be brand and vendor preference (I've got a friend who's big on the EVGA Nvidia cards). Still, something folks have often said, and just as a warning, never get something because of a rebate. Many mail-in rebates are slow to arrive, if they even bother showing up. Granted, all of the comparable cards to the one you chose are about the same price and carry similar rebates, so that's not going to be much of a factor.
Case: I get you are planning on an HTPC, but not sure on how the video card you picked fits into a microATX case. I don't expect it'd be a problem, but something you'll want to make 100% sure of before ordering. I'm not a microATX/ITX person myself, I just feel better having a mid-tower ATX case's airflow. If you were to consider the MicroCenter offer I mentioned, you WOULD have to step up to the mid-tower level.
Power Supply: If that $100 you have left isn't being thrown to an OS license or peripherals (didn't see them mentioned has part of the $800 budget), I'd spend the bit more for a higher-end PSU. Something 80+ GOLD is what I'd aim for, preferably by one of the top brands, like Corsair or SeaSonic (and they supply the parts for some other PSU manufacturers, but I don't follow them well enough to comment on which).
Optical Drive: Pick one, shouldn't matter. I don't do Blu-Ray, so I got a cheap LG DVD-R drive, but for an HTPC, I'm guessing you'll want such a thing.