I'm not sure about a temp gauge on top, but if you're looking for accuracy, the Won Pro Heat II is the way to go. It has a control unit with a digital temp readout and a separate temp control probe. I have used them extensively and have been very impressed with their performance so far. They aren't cheap, but aren't really out of line when compared to other top line heaters either.
Life is not measured by the number of breaths we take, but by the moments that take our breath away.