The nicest pair of pants that I own I got from Banana republic. They're a wide-legged, dark grey trouser. They're super comfy and really professional looking. I think if you had slacks like that, or any dark grey slacks, you could pair it with a colorful blouse and be ok. The key is to accessorize. Have some bracelets, and maybe some pretty ears. if you have big ears, or just a lot going on with the top, wear your hair up.
something this shape
http://bananarepublic.gap.com/browse...d=1&pid=739936
with pants like this
http://bananarepublic.gap.com/browse...scid=702760002
(the wide waist band controls tummy. I love it)
and a blazer like this
http://bananarepublic.gap.com/browse...scid=702700002 would be great.
ignore the colors, and just look at the shapes, to get an idea. I'm not real sure how clothes fall on a pair shaped body, so just use this as a general idea of where to start.