A New Era in CSS Centric Design?
No, it doesn't. Seeing as web programming is my job, I can tell yout that tables - horrible as they may be - make a better layout tool than CSS.
I have to disagree with you here. I've been a web programmer professionaly for 2 years and been doing it on my own since back when PHP3 was a new and cool language (looking back, I get to thinking, why the hell did I think php3 was a good language?). Back then, CSS was still fairly young and didn't have near as much standard support as it does now. Building a website without tables was laughable. When I started getting back into PHP and web programming in general, I picked back up using tables like before. A guy I worked with at my current place of employment showed me how far CSS support has gone since I dropped out of the scene. I was impressed, to say the least (even though the company's websites were all still done using tables). I quickly started learning of the benefits of CSS and using valid (X)HTML. Now, whenever I have to build a website, I have my HTML already written (for the most part) and just upload the necessary files. I then write the CSS and position everything where they need to be (unless the layout is drastically different from others). Using CSS has saved me at least an hours worth of time when starting a website. Then, when they want to redesign, it's just switching out graphics and minor changes to the HTML/CSS. If only my boss could see the time it would save by switching over from tables, instead, they saw the amount of time it took to overcome the learning curve. That's one of the key things that CSS Zen Garden showcases. You can have a completely different site using identical HTML (alot of that is in the graphics the site uses but, still). I find it fun to browse through the Special Effects category of CSS Zen and see just how completely different people make that site look just using CSS alone.
I've found equal-height columns to be a very negative design mechanism. It looks great in Photoshop, but horribly fails when the site is complete. Invariably, the client will be too absent-minded to realize that if one column has substantially more content then the other, then the other column will be incredibly long with very little content (the people of the aformentioned site did that and then called complaining about their own content).
There are some CSS tricks you can use to your advantage, though, that will work great in (what I call) the big 3 (Windows: IE, FF, Opera; Mac: Safari, FF, Opera). You can have an entire column wrapped in a single div, set the width of that div (with no padding, margin nor border), then use divs for the content inside that div. Leave the width alone and set the necessary margin, padding and borders. That way, there's no need for hacks around IE's box model bug or anything. It can potentially create some wasted div space in the HTML, which is undesirable but unavoidable until browsers all become more aligned.
It sounds like your only problem is that CSS just hasn't clicked for you yet. (Forgive me if I'm wrong, you probably have more experience than I do and I'm by no means a CSS genius or anything, that's just what it sounds like to me) If you just take your time and force yourself to only use tables were appropriate or absolutely necessary, you'll get to a point where you can do almost anything you could with tables without having to use ugly hacks and do it easier and quicker than before.
Really, it all comes down to what you're comfortable with. If you feel more comfortable using tables and believe you can produce a better product for the client with them, then continue doing so. I, personally, view CSS and standards-compliant CSS/HTML as something that will only become more important (from clients believing it to be of upmost importance to enabling alternative User Agents to access the (X)HTML to use it in different and unique ways). Plus, informing potential clients that your sites are standards-compliant makes for a good buzz-word (you could even direct them to a link to w3c's validator and walk him through validating one of the companies websites for added emphasis).