the long and short of it is that you need a good one.
A client, had a site which for one reason or another was inaccessible, I remade the content choosing this (cheap) URL a cumbersome www.frenchmediterraneanproperty.info. a nightmare to type ( but once in your browser cache it comes up straight away ).
Any combo of a Google 'browser bar' search using the keywords French Mediterranean and Property will bring this site up... So, I think that if your key (descriptive) words, are in your URL, you have a better chance of climbing, than if your URL say, only comprises your name...We have all done it, Google your own name. Ronald Birks is plastered all over the web, several mentions have emanated from SFN, thanks guys!
However this is not much use as you would need to know my name, not my business sector. The obscure spelling of the name helps, but also I publish lots of pics, which when clicked on in the images search of Google....here, many pics come back to SFN, aw it's nothing guys!
Word splitting is also food for thought. Apostrophes, I believe aren't permissible, underscores Ugly, can you use Upper and Lower....I have many sites to do with Cap D'Agde ...difficult to URLerise!
is probably the best option.