I have been using mandigo theme for my blogs. Really easy to replace the header with your own. I would recommend to those who wants a more colourful look. Check it out at my signature.
Take care in selecting your template, I ended up getting a site removed from live.com because the bot saw something weird about it. The site was being updated daily, but live stopped crawling around the same time I tried a particular template. Google didn't mind it though.
In reality, yes, those templates can have nasty stuff in there. It all runs in php and I'm sure someone could sneak something in there and get some important info. I never thought about this before, but I'd be more cautious now. A beginner may not know what to look for. Not trying to scare anyone, just don't download templates from sites other than what wordpress links to, just to be safe. In my case, I think someone just didn't know AJAX very well , or live just didn't know how to handle the site. As for url's, I don't know of any. I am just speculating, as it "could" happen. Except for the part where my site stopped being crawled.