overlay
css is good... lots of tricks, simple, loads fast compared to overlayed, and easy to learn... optimum, but it can never be the best.
overlay is the next level. got tired of the same profile arrangement that friendster gives. you can incorporate your css, make tweaks to load fast, rearrange the layout. have your own set of menu and contents. it not easy compared to css because mainly it involves graphics and it's like making a website out of your profile... its the real deal.