Never change your blog template if you have no idea what you're doing. I made the mistake of doing just that a couple days ago. Since I'm cheap but don't want to use Blogger's default templates, I did a search online for "Free blogger xml templates" and came up with a few sites. I had a few requirements in mind. I wanted one of the more colorful templates since many of the black text on white layouts tend to blend together and all look the same. I also wanted a three-column template. So, my choices were limited.
When I went to install the first template (and second. And third.), the widgets or, as blogger likes to call them, page elements would go flying all over the screen. My twitter gadget would be up in the upper left-hand corner of the page while other gadgets were nowhere to be seen. I finally found one that seems sort of okay but it isn't perfect. Where the date is supposed to be, it's reading "undefined" so my search for a new blog template will continue. I just don't want to deal with that frustration right now.
Updated: *cheer* I found a new one that will do. It needs some editing but even I can do it. :D