Do you have a problem with the cord coming out of the feeding hole?
I have that same tank. I can honestly say, if you really want to go for looks, take out the undergravel filter. In my opinion, it really doesn't work too well and just takes up space. You could leave the air stone and air pump though, if you wanted to, for water movement. Then you could remove the clear cover and the heater cord could stick out the back.
Just a suggestion though.