whats wrong with sketchup?

many architects and designers are using it including myself. if you are student, archicad offers free software from their website.
Which software depends where you are working or want to work. Some countries have a high preference for ArchiCad, Vectorworks, AutoCAD (PC) Microstation, amongst many others
So the next question is what do you wish to produce?
Are you trying to do 3D work, (Rhino, 3d Studio Max, etc) which both archicad and vectorworks and sketchup all do well, sketchup is really easy to use in this manner, or are you after documentation software which all of the above are good at as well, but you need to build in 3d in archicad to generate default drawings which you further work or Vectorworks which is in reverse. Are you after 2d drafting then defo vectorworks but it is pricy, though they do have a discounted student version as well.
under $100 mmm... you might be able to find a generic design house program, but I would stick to the sketchup