Hard to really define where bulge stops and halo begins, smooth transition. Definition is generally tied to the density of stars, which decreases with the distance from the center. Rough number is that the bulge extends about 10,000 light-years from the center. The disk component bisects the spheroidal component. Where most of the gas and dust is found and, of course, star formation.
Spirals are the most common type of large galaxy.
Elliptical galaxies Look like ellipses from every angle, though the size of the ellipse you see will depend on the angle. Elliptical galaxies don't have disks , in general. Exceptions are caused by galaxies that have merged together. Looks very similar to the spheroidal component of a spiral galaxy. Ellipticals are mostly found in clusters.