People use to worry that a long domain name would be hard for people to remember as if it were a long phone number. But the reality is that your new domain name can can be almost any length as long as it describes your business well.
While I’d avoid BigTonysAllKazooPolkaBand.com* due to excessive length, it’s not inappropriate if, in fact, you are Big Tony and you lead an All Kazoo Polka band.
Now if the name you want is already taken, you’ll be better off finding another name. If the site is established, the registrant isn’t going to be too keen on giving it up and they won’t do it cheaply. If it’s simply a squatter, you might be able to negotiate a good price. Just keep in mind that a year of domain registration is usually under $10, so if you’re paying a few thousand dollars to a squatter the name should be really fantastic.
* Factoid of the day – once upon a time I was the owner of BigTonysAllKazooPolkaBand.com