A completely straight staircase is the simplest staircase model. Is somewhat more space-consuming than, for example, an L-shaped staircase.
Keep in mind that the ceiling height and the size of the opening together will determine whether you can handle the clearance (ie you can take a few steps up the stairs and not hit your head on the ceiling). The stairs can normally start a step or two outside the opening and you can walk on them without hitting your head, but always check these measurements. If you make the opening larger than the stairs, you don't have to think about whether you can handle the clearance.
Different types of railings can be experienced differently in a straight design. In general, short railing sections, separated by a post, feel the most stable.