FranticFish - 1:14 pm on Sep 8, 2010 (gmt 0)
I'd echo Maximillanos' comments. Look but don't touch until you're sure you know what you're doing. If your site has been around for eight years then it might have some great links to pages that you are removing or renaming.
First thing, before you do anything else:
Using Analytics or another stats program, look at where your traffic currently comes from. What sites are in your referrer log? What pages are bringing in traffic? On what terms?
Next, find out who links to you. A good start is the Yahoo SiteExplorer Tool, but there are others (N.B. all of the free tools are based on the Yahoo data, but you might prefer some of their user interfaces). Google Webmaster Tools will give you some information. It will also show ranking data. There are competitive tools that aim to give complete data because they crawl the web independently of Google and have their own link data set. At least one of the two I know is free for your own site. I've PM'd you details (not affiliated with either).
Check how many pages you have in Google, and which ones. Check your error logs for 404s. Make sure that people aren't linking to pages that don't exist. Either put the pages back or at least put a 301 redirect to an equivalent page that offers the same or similar content.
That's before you touch one thing on your site! Understand what's happening first.
Next comes keyword research, which will inform your SEO strategy as regards content for the site, links to it and other activity.