Keywords in the domain for SEO?

Ok..So I've heard and seen first hand the importance of having your main keyword in the domain.
In some cases...especially long tail keywords... it can be as simple as getting the domain based on the keyword and you rank.

I have a question...Many times you can't get the domain you want..
Would it still make a difference if I were to buy a domain and append a letter at the end?
For example:
Instead of bestcardeals.com ...would bestcardealsX.com work?

Obviously not as well as the former..but would it help in any way rather then just going for a brand name?

Yes it will give you an added benefit, depending on the competition of that particular phrase you are targeting.

It cant hurt you, as far as I know. Just saves you time for that particular phrase.

You may just want to stick a common word into your keyword url. Try something like thebestcardeals.com. Just like in a search results, google won't see the word "the". So you get all the taste of a regular keyword.

definitely a added advantage over your competition. Try something like this for even better result

http://bestgolfclub/golfclub/best-golf-club.html ---> Google will love you

Yup I agree, having it in the domain/subdomain will definitely help. I usually stick to broad-termed domain names so I can use subdomains for targeting longer-tailed keywords.

As far as I'm concerned, and until studies show me otherwise,

imtheshit.com is the same as imtheshit.whatever.com

as far as SEO is concerned - root domain doesn't matter as long as the kW is in the URL.

Hope this helps,
dN