I'm guessing it will matter. As google will probably see by domain name that your site is concentrated about this subject, and if your content is also good then I'm pretty sure you will get better rank.
For example. If you search "Game Cheats", and probably there's tons of sites that are concentrated on this, you get 3 pages of sites which all contain "Game" or "Cheat" in their domain or at least sub-domain. After that there came one site which didn't, but this one had "Cheats" as directory name..
I don't know it 100%, but I'm guessing domain name will matter a little. Cant be too big influence though.
EDIT: Also, in firefox, and I think also in latest IE - when you type into address-bar something like "Rotten Tomatoes" then it will automatically search it from Google. I use it, and I'm sure a lot of people use it as well to search Google. Now, if you make a site
www.rottentomatoes.com and slowly start to build your Google rank up, then apparently if someone searches "Rotten Tomatoes" from address-bar, then Google will automatically direct them to your site, which can give you a lot of good traffic. This would only work with terms that people search a lot.
For example, at least in firefox, if you type "Bike Guide" or even "Bike guid" to your firefox address bar it would direct you to
www.bikeguide.org, now if I check "Rotten Tomatoes" which I randomly chose as example, also directs you to site "www.rottentomatoes.com" which is apparently Movies/Games Review/Preview site, same with "Flowering help" which points you to
www.thegardenhelper.com . But if you type in for example "Potato gun" it will just go to Google and search term "Potato Gun" and give you all the results, because there is no GOOD site, which has similar domain. There is "Potatogun.com" put that's just this stupid domain-reservation site, inputting "Website Babble" will also direct you to Google.. don't know why, as this site will come as first result, and has Google rank "3", same as bike guide..
Like I said, I'm not sure but it seems that domain name does matter..