When I've used spray paint in the past, I just used whatever cheap can of black I could find. I think cleaning the glass really well, and doing many, many, light coats matters more then brand/cost.
More recently I've used brush-on latex. Took a lot more time, but unlike spray paint, it's something I could do in my studio apartment. It took a lot more coats, mostly to try and fill in the brush stroke lines. Using a roller will probably make it easier, and someone else on here advised thinning the latex, which seemed to work better the second tank I painted. You could probably get away with less, if you just want a black background, I wanted it thorough enough I couldn't see light through it (used a flashlight in a dark room to find thin spots/gaps)
I've heard a lot of good things about spray-on plasti-dip, mostly that it goes on easier/thicker, and removal is pretty easy if you change your mind. I haven't tried it myself, but probably will next time I paint.
Anyways, whatever method you use, cleaning the glass really well is probably the most important. I think the last tank I did I wiped it down with both vinegar, and then later, acetone.