I'm in the same boat. However, I started planning long before ordering the processor and, when all is said and done, my build will have been coordinated over the course of nearly 3 months. I can't complain because in choosing a few component options in advance and then pouncing on deals as they become available I've literally saved myself hundreds of dollars. (super cool that you can see pricing history on PCPP to ensure that you're getting everything while they're at rock bottom) What was originally an $800+ build that I was willing to extend to $1000 is currently tracking to finish sub-$600. (doesn't include a monitor since I already had a 1080p Asus that has been fine)
Anyway, I too had to consider form factor. I wanted to get a full sized ATX board since it allows for more options and removes compromises, but as an apartment dweller there just wasn't a good way to integrate it into my current living situation. For where I wanted to place the tower I needed it to be under 16" tall. (accounts for sufficient airflow) There's simply nothing out there unless I was willing to go the HTPC route (
this Silverstone case looks lovely) but that would require some heavy reconfiguration of
my home theater and it was far from the most convenient option.
I swung in the opposite direction and gravitated toward an mITX build. The
Thermaltake Core V1 in particular piqued my interest since its footprint is ultra-compact, it can house most full-sized components, and it allows for great airflow. My concerns with going this route, however, were that I really only had one mobo option that I felt comfortable going with after doing a ton of research, (the Asus Z97I-Plus) I would be limited to 16gb RAM, (not important now, but who knows what the future may hold and I've read a lot of debate/speculation on the subject) CPU cooler clearance is limited meaning that I would have to go with a less than ideal option, and the maximum graphics card length is limited stunting my options for future upgrades. The Fractal Node 304 alleviates some of these issues, but I honestly dislike the aesthetics of that case and airflow doesn't appear to be anything special with it.
I finally landed on mATX and purchased a
Cooler Master N200 case when it was on sale for $35. I obviously haven't built with it yet, but I did already unbox it to inspect for damage and I'm more than pleased with the build quality and it ticks all the boxes I was looking for. It's just shy of 15" tall, (and shorter than that if you remove the feet) houses pretty much anything you want to throw in it, (supports the Gigabyte Windforce cards no problem and allows for bulky CPU coolers like the Hyper 212 Evo) and has great airflow options with its front mesh design. (I'm planning to add the optional second fan) In addition, mATX can allow for SLI/Crossfire if that's your thing and the boards can support 32GB RAM. (again, probably not important for gaming but I'd rather have the option) It also gave me a good deal of mobo options that I personally deemed worth considering and I ended up getting a great price on
this Gigabyte. The only compromise that I feel like I made was getting a mobo that doesn't support M.2 thus limiting that as a future upgrade option, but that wasn't high priority to me.
As a first time builder, this process has been far from easy -- but it's already been fun and the knowledge gained has been incredibly rewarding. Just keep reading and you're sure to find something that will mitigate (eliminate?) compromise.