A lot of people take a year off, but it's not the year off that helps or hurts their application, it's what they do
during that time that matters. I don't think a year of programming work will hurt you, as a regular job is certainly better than a year of nothing, but I don't think it's that great for grad schools either. My basis for this opinion is the professors and admissions committee members I've spoken to that unanimously and strongly say that letters from people you did research with or took physics classes from are much
preferred to letters from bosses even in science-related industry, and even if the job was recent but the research and classes were very old. The view seems to be that research and jobs are quite different and require different skills, and that if you want to be a researcher
then you should spend the year doing research and showing you have research skills.
So if you wanted to use the year to really bolster your app, a programming job is probably mediocre and a research job is the way to go. However, if you feel your app is relatively solid and just want to chill for a year and put away some money from a good-paying job, maybe study and retake the PGRE, I definitely don't think it will hurt you.
For your chances, if you go through the three stickied profile threads and do a search for "madison" you'll find a lot of information on what types of applications get accepted to or rejected from madison and you can judge your chances that way. Also http://www.gradschoolshopper.com