I think we’re at a stage where a growing percentage of designers will dismiss your work if they see tables used in the source code. Table proponents generally don’t care one way or another - if anything, they’re impressed by pure CSS layouts. So for the sake of job security, if nothing else, I recommend moving away from tables ASAP.
That said, I still use them (I’m not a designer, though) ;-)
The topic is the ever-raging tables vs. CSS debate. The CSS Zen Garden converted me to CSS :-) But since I have much more experience working with tables for layout, it's a lot easier for me to use them - especially for quick and dirty website work.