How many - are too many on domain and url?

some of my pages have the title a URL

[walkman]

and I'm thinking. Right now my domain doesn't have a - or anything (a new one I just registered might have one though) but some of the titles are used as URL. It's a db based and the only way I can make it spiderable is by linking the individual searches and making a sitemap. Worked great. On some, I just leave as it is, with blanks that show up as www.domain.com/word1%20word2%20word3 on the search engines url. As you know it will work even as www.domain.com/word word2 word3.

No .html or anything. This is re-written and I'm thinking if I should substitute the space /%20 with a dash. Pros and cons? Getting banned or penalized is a con :).

[troels nybo nielsen]

A dash certainly looks nicer in a URL in a SERP than %20. And it gives a slightly shorter URL which is always an advantage.

I believe that there is a general consensus that two dashes in a domain name or a file name is alright while three look somewhat spammy. There are good linguistic reasons for this. Think of all the three word phrases (like some people's names ;) ) that come quite naturally as entities while four words begin to sound like a complete sentence.

[walkman]

so the answer is don't do it :)
The title is generated on the fly and includes the "search term" /keyword so it's not that bad on the Serps..

thanks,