Thanks for the nice comments about the site, it's always good to get feedback :)
There is always a fine line when it comes to link exchanging (think I have about 450 links in total on my site at the moment). The problem is when you use link farms because SE's know who these are are are starting to block and ban them (Link farms will go the same route and posting on guestbooks and blogs in the near future imo).
I don't use link farms and I manually check each link I have on my sites. At the moment I can see no benifit of having each link in its own catagory but I will probably have to review this at a later date. The method I use at the moment would cause me a lot of problems trying to place the links in a proper catagory so at this time I don't do it.
Content and easy navigation is still king but by linking with a large number of other web site my site gets the cache refreshed often (normally every 1 to 2 days) but today I've altered my link exchange method slightly on my other sites to see if I can speed the process up even further. Because I update so often my goal is to get it cached at least once a day.
I have 10 main sites that have a lot of links and 30 others that are in the process. I do this so when I've designed a new site or have a new SEO contract I can get the new site indexed much faster than trying from scratch. By having a large, well established site base to work with SEO work is much easier and faster.
I only started link exchanging in the 3rd quater of last year and I've already seen the hits on my own site rise from 400 a month to 20,000 a month and my logs are showing that this is continuing to rise at a rate of 5,000 a month.
There is so much to web development and it is much harder than it used to be. Links are just one part of an ever increasing phase of web design and promotion.
One of the best tips I can give at the moment is learn CSS and use DIVs instead of tables where possible. I've recently had someone contact me asking to help with SEO and when I looked at his page it was 310 lines long and bloated with so much html code the SE's were having trouble indexing it. By using CSS and divs I reduced the html lines from 310 to 65 and the page size from 35kb to 6kb and it is now a very SE friendly web page.
The other major benefit of DIVs is, unlike tables, you don't have to wait for the whole page to load before it displays.
My god, I could go on forever with design tips, I better shut up now before this message heads towards a million lines :)