We currently rebranded everything from DropClock.com to eFreeme.com. The phonetics of the name of DropClock weren't that good and in addition most people confused it with DropBox. eFreeme.com on the other hand was easily understandable when saying it the first time. With that being said, we are currently selling DropClock.com domain in addition to 6000 stickers that are tailored to some sort of Buy/Sell website. We have over 5K invested in this brand and to just push it aside was a bit of a sore spot for me, but hoping that it's worth it in the long run.
My previous company was named UsedVancouver.com, unfortunately we needed to register every city in the world, and we did, so we ended up managing about 1200 domains.... OUCH. So if you have a product that is going to scale to individual cities make sure you make it generic enough to just "subdomain" it like craigslist does.
A short and catchy domain is what you want. However it's difficult to find those, but they are out there! And more importantly it's good to find a domain search engine that gives you lots of options. Good luck!