Search Engine preference

Which URL is better?

[Advenlo]

Do search engines prefer www.domain.com/keyword1-keyword2.htm to www.domain.com/keyword1keyword2.htm or is there no discernable difference?

Thanks in advance for answering what's probably a dumn question

[SEOMike]

I tend to use:

keyword1_keyword2.whatever

That's worked pretty well for me. Serachers that pay any attention to page names in the SERPS would probably click something like this before something like

product.asp?=12346541899874651sdf8sdc32sdf465zx1dvc
:)