What about when the old URL no longer exists at all (page no longer saved on server) - how can you do a 301?

I would say that it is generally better to hire a separate person for SEO and SEM. There are so many different tasks that an SEO can be doing to move the organization forward on the SEO front that I think it is often a mistake for SEOs to be given additional tasks like PPC, or managing the company's social media, that will take their focus off doing SEO really well. Also, SEO is changing so fast that it can be a lot to ask to have your SEO stay current on the latest in SEO and also stay up to date on the PPC world as well.

What are some things to consider or things to evaluate when deciding whether you should focus resources on creating new pages (to cover more related topics) versus improving existing pages (adding more useful information, etc.)?

One way it could hurt your SEO is if people who link to your site mistakenly link to .com instead of .net which could reduce your inbound links.

Usually the first offer is less than they are willing to pay. I would consider replying with something like:

I was actually thinking in the range of 40-42K because I am able to increase the company's bottom line by attracting customers through free targeted traffic to the site. Is this within your budget?

There are certainly places that will pay a higher salary as well for an SEO specialist, but there may also be a trade off with greater pressure, longer hours, and more responsibilities.

Another idea, if your company is okay with it, is to start your own SEO agency in the evenings to earn extra income and see how you like working with clients.

I recently submitted to JoeAnt after looking at the SEOMoz directory list. The page I wanted to submit to had a SEOMoz page authority of 39/100 and about 5 links on the page, which looked promising enough to pay 39.99. The good thing about JoeAnt is you don't have to pay every year like other directories.