Accessories Wall-USB Plug

I'm sorry if someone has already started a thread on this before but I searched and searched and couldn't find anything. I was looking for recommendations for a wall plug to use with the USB cable. I know anything rated at 850mA or higher should do fine, but I was just wondering if anyone had some good experiences with them that they could share. Charging from the USB on my laptop at work is a it of a hassle because I'm up and down with it all day so I don't want to have to drag it around.