My 2 cents:
I recently did a few PPV tests which went a little somethin' like this:
Test 1:
LP made in Photoslop, saved as low-quality image VS. Identical LP made as HTML
I couldn't believe it but the image one performed significantly better.
Test 2:
Low quality image LP around 30k VS. Identical high-quality image LP around 70k. Winner was the high-quality/slower loading one.
So if you're talking about CSS vs. tables for an LP, just do whichever is quicker because it doesn't matter as long as it shows up correctly in IE and Firefox.