My rule of thumb is that 3 inches is the maximum height for work and that platforms should be avoided in the office. Of course, there may be some exceptions, for example, some heels that technically have a platform front are designed or covered in outer material so that the platform is hidden. The biggest variable is your office culture. If you work at a fashion magazine, then chances are the norm will be to wear heels considerably higher than 3 inches and if you work in a law office you might feel that a wedge is too casual and that only a navy or black sensible pump will be acceptable. But regardless of your job, you should choose a shoe that is comfortable.
Below the slideshow shows a few shoe options based on different office environments and dress codes, but only you know what will and will not be viewed as appropriate in your field. Let me know in the comments what you look for in a shoe for work. Do you rotate through several styles or wear the same one every day? Comfort or style (or hopefully you get both)? Are your shoes a bright and cheery hue or do you stick to neutrals? Share your thoughts as well as links to any shoes that you love for both comfort and style!