I'm not saying anything against people who don't like it, in fact I think you'll find I said they were the experts.
I don't claim to be a "designer" myself, and I'm no expert, I'm a beginner. Only bought the site in May, and started learning HTML and CSS then.
sorry, I read that as "it was written so you can see how it works, that's how I want it and only the experts see that, if you don't that means you're not an expert." My apologies.
As inquisitor said, lose the <center>s, use text-align: center; if you want to centralise text and define and width and use margin: 0 auto; if you want to centralise a block level element within its parent. And don't put <br/> tags ouside of block level elements (p,div,li etc), use a horizontal rule if you have to.