Lol if I may chime in about that tank -
The paint (yeah looks like latex) has stayed on... pretty well for the most part. Considering its latex i think its doing good. It is on the outside of course. I find that any firm pointed impact leaves a big mark, but the colour itself looks really good from the front of the tank. I dont know what is inside the overflow box (brett can you take a look at the thread and let me know what you think?)...
Like Brett said, acrylic (black or blue whatever) inside the tank if you want to do inside, but the problem that comes with that is if you need to scrape coraline off the back you need to make sure you use acrylic safe (plastic) 'blades" or scrub pads. Also the back can be scratched more easily. Inside or around an overflow box the acrylic is commonly used.
Krylon Fusion is wicked stuff... inside the tank, its fine, but if you want to spray the back outside then you can scrape the inside glass any-which way. If you spray evenly it leaves a beautifully smooth coat and stays on very well. I use it on ALL my tanks (all the backs are black). It comes in many colours.
Most people go with blue or black background for tanks... blue is nice, but personally I go with black.. It tends to add depth to the aquarium, and makes the contents stand out (and less attention drawn to the back glass than blue). One of my tanks is blue and you notice the tank colour a lot more and the attention is taken away from the contents. Pity because its starphire glass, lol. But it does make it look incredibly bright i find.
Sorry bout the essay!
Cheers,
Chris