How important is a good site map to SEO?

How do you guys generate your site maps?

If there is an old thread about this, please link me to it, I tried the search function, but I'm probably not very good at it.

I've used some free online tools. They're ok, but I'm not sure I'm using the best one. ( I use the first one of this delicious search http://delicious.com/search?p=create...l_icio_us&lc=0 )

Does DW have an XML site map generator?

Have any of you used Google's Python site map generator? It looks somewhat complicated to use if you've never work w/ python (like me), but is it worth it to work through it?

thanks for the help!