Originally Posted by
Spats
2 vs. 3 button: yes, 2 button is safer. 3-button can work if the buttons are lower and closer together...it's the ones that button waaaaay up high that go in and out of fashion. Mostly it's tall guys who can do 3-button, but don't rule it completely out if it makes you look good. Odin makes a good point that the extra-low 2-button is bad, too (unless you're astoundingly short). Basically you don't want anything extreme or "stylish" on either end.
Buzz: No square toe shoes like those in the picture. The shoe on top is not a business shoe and says "I am a security guard, ignore me". The bottom shoe is OK if you have several pairs and can choose appropriate to the occasion, but for your only shoe, mitch is absolutely correct -- a classic cap toe oxford will never go out of style. Ditto for Allen-Edmonds (expensive) or Johnston and Murphy (a bit cheaper but still legit).
For shirts, don't just get multiple white shirts. Light blue and/or French blue are always legit. Other patterns and shades tend to go in and out every few years, like ties. If you need to wear a suit often enough to need more than a couple dress shirts, you may have to resign yourself to buying shirts and ties every few years.
Get the sleeves and body of your dress shirts tapered to fit you. This costs about $15 at Nordstrom and will make you look good.