Welcome to Sitepoint
I guess you must have been busy for the last ten years because as Max said above this topic has been done to death and there isn't really anything left to say that hasn't already been well said and documented (and to be honest I don't think this late in the game that we could convince you otherwise anyway ).
If you do a search on the forums you will find many similar topics with the same pros and cons and the answers you get here are likely to be the same.
I think the main question is really whether you are willing to take the time to learn something new or are happy to jog along comfortably as you are doing. The right reasons for learning CSS are that tables were meant for tabular data and not layout (although they have been coerced to do the job well). If you don't care about that then I doubt there is little we can do to persuade you otherwise.
The fact that CSS takes some time to learn and to do properly is not really an issue as that is the case when learning any new skills and it's always more comfortable to fall back on what you know.
Browsers these days are very good at rendering CSS layouts and if you know what you are doing there is no problem with consistency. Of course there's a steep learning curve at first but anything worth doing is worth doing well. In my experience its tables when used for layout that are more inconsistent between browsers because they are doing a job that they weren't really designed for. They do some things really well but they also do a lot of things badly.
If you want to move forward then CSS is the way to go. If you are happy where you are then you may think why bother but if you care about your profession, your clients and your visitors then there is no option but to move forward and drop tables for layout where possible.
You never know you might end up liking it:)
Hmm, that doesn't seem to be CSS related as such.
I don't know much about DW templates but I believe that once you change the template file you have to upload all the pages that use that template. That would be a showstopper on some of the 1000 page plus sites I've worked on.
You would be better of with SSI and just make changes to the one file and upload one file.
2) Faster Load Times Because of Lighter Code – I remember load times being a major issue when I first got started but it doesn’t seem to be the case anymore with so few people on dialup. I can’t tell any discernable speed difference between a table layout and a CSS layout’s load time. (Yes, I like clean code too.) Heavy image use and Flash still seem to be the biggest factors in speed. If the human eye can’t tell any difference, then what’s the point? And server space/bandwidth doesn’t seem to be an issue anymore either. Space on the server for all of my client’s sites is generally 1/16 of capacity.
The fact still remains that table markup can double the html size so whether it's a small issue for you using broadband or a big issue for users on dialup, it's still an issue that doesn't need to be in the mix. There can never be a case made for code bloat just because systems can handle it these days.
3) SEO – From what I can tell, search engines aren’t indexing or ranking CSS layouts higher than table layouts. The algorithms used for ranking most often are content and inbound links. The spiders are highly efficient at discerning code from content. So what difference does it make?
There is an important issue in content to code ratio and you will find that when you have more code than content your search rankings will be hurt. Again, the question is why risk it in the first place? You have nothing to lose but more to gain from using CSS.
4) Separation of Style and Content – I guess this one is related #1, ease of updating? This is what Dreamweaver template files do. It separates style from content (editable/un-editable). I don’t know about you, but generally speaking what my clients want most often is to update the content. I don’t understand why it would be easier to update content using CSS more so than tables. (Remember, I DO use CSS for formatting.) If they want to tweak something in the design, again, piece of cake to do. Just change the template file. It’s not hard.
Again this doesn't seem to be a css question. What has CSS got to do with updating content on a site?
You are talking about the benefits of DW templates which has little to do with CSS for layout. Even if you use CSS you will still have html in your template so the issue is the same. Using CSS doesn't automatically mean that you can completely change the look and structure of your site without changing the html although some times you may be able to make significant changes without resorting to html changes but that was never its primary purpose.
Separating presentation from content means removing the presentational attributes from the html so that you don't mix nested tables and font tags just to make the layout look the way you want.
You really should be looking at SSI (server side includes) if you want to simplify maintenance of repetitive sections.
Disadvantages to using CSS for layout
1) Inconsistent Browser Support - Different browsers will render CSS layout differently as a result of browser bugs or lack of support for various CSS features. This is no small drawback!! It’s huge.
That's just not true these days and modern browsers support css2.1 very well. There are bugs and inconsistencies but most of the problems we see in the forums daily are a result of author mistakes and not a problem with the browser.
It all boils down to taking the time to do the thing properly. It's not easy and it's not going to be quick but who said that it should be? It's a subtle and complicated mark up system that needs to be understood and applied correctly.
Right or wrong, I LOVE spending most of my time designing. For me, the rest is a necessary evil to get the design into the medium.
And there lies the crux of the problem You have it the wrong way around. It should be the medium that dictates your design and not vice versa. Times have changed and are still changing fast. We no longer have 800x 600px to worry about but we have 50" monitors and 160px mobiles to contend with. You have to move forward with the times or get left behind.