depends on the type of organization. Corporte IT go for suits. If you are interviewing for a more trendy / creative tech company like razorfish or twitter than skip the suit.
Need to have one suit that fit you and you can breathe and move properly. I got mine as a steal from Macys and it’s my lucky interview suit because I think I am more comfortable also confident in it. Same goes for shoes. Nothing more annoying that a uncomfortable suits and shoes to take away from feeling your best at a interview.