This is probably the most common dilemma of poly modeling - trying to cut holes with sharp corners into curved surfaces.
opt 1. Increase the initial density of the cylinder so when you cut in the edges to tighten the corners you do not have narrow polygons relative to the others. If you google you can find examples of "cutting holes with sharp corners into curved surfaces". I'd venture to say that in almost all cases people try to cut openings into a mesh that is far to sparse. Either start with a mesh dense enough to support the opening or create a base mesh with control edges for initial column shape and then subdivide it a couple division levels and then extrude in the holes.
opt 2. you can create separate geometry so you don't have to carry edges through the entire mesh. Try to imagine how that pedestal is really built. It's most likely built from multiple pieces. Unless the camera shot calls for an extreme close up you are not going to tell if its a single piece or a number of pieces pushed into each other.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram; 26-10-2013 at 11:45 AM.