I was never impressed with Erwin, I did use Popkin system architect for many years, but these tools are far too expensive for most companies. I have Visio included with Technet/msdn subscription and I probably will buy at some time dezign http://www.datanamic.com/dezign/index.html
I used the demos and was impressed - much cheaper too!
[font="Comic Sans MS"]The GrumpyOldDBA[/font]
www.grumpyolddba.co.uk
http://sqlblogcasts.com/blogs/grumpyolddba/