And: Designers may be very interested in learning more about how you intend on printing your posters (screenprint/offset/digital/…), on what kind of paper, and so on… (This IS important, as they sure are interested in getting their work published, bought & seen; but not printed on cheap & thin copy paper, which would devaluate their work and your whole ‘product’ as well.)
http://namecheap.com & http://name.com (*These are ones I currently use [namecheap.com since more than 10 years I just realised] and I am pretty happy with them, so far)
From a personal perspective, I'd say choose productxapp.com, if it is an app, over getproductx.com. (Or choose a domain hack, like produc.tx, if that would be possible/available?)
But you always should keep in mind and accept the fact that some of your target audience and visitors will end up at productx.com anyway.
How to get attention? Maybe just like everywhere else: Provide good content, worth sharing! (And then your links and posts on HN will get upvoted by Europeans AND Americans AND everyone else. ;)