I am curious to which is better. If you are creating a website with a specific niche, than do you want to use a domain name which has that niche name in it's title? An example... If I made a site about salads (just an example ) than would I want to use something like saladtown.xxx or could using a non related domain name do just as well, like poogy.xxx? (thats an example only) Like eBay, they are very successful and there name does not contain "auction".
Short and memorable is good for large, successful businesses, keyworded is good for low traffic websites with search engines being the main source of traffic.
It is always better to go in for key word rich title to select your domain name because half of your SEO work is done already. Key word in the domain name is definitely advantageous. But take care to avoid too lengthy title and let it be short and crisp (if possible like eBay!). eBay became famous for some thing other than keyword rich title. That's another story. We can't replicate others success exactly