Which career is best graphic designer or architect?

They are both great careers. Architecture is a slightly higher difficulty factor in the sense there are many aspects to specialize in and a longer learning curve seeing buildings and large structures take years from planning to design to actual blueprints. Other types are Landscape, Electrical,Mechanical and many more.

Graphic design has more of an art feel to it and once learned you can make your mark in many ways in many industries. From advertising to packaging there are many uses for graphic designers and a quicker path to excel at a job although the top end in the movie industry for example could be as challenging as designing and drawing plans to build a large building or structure

Now all said I will say I am not an expert at either but have worked with both and what I stated is in part my opinion as I have done no studies to give you a factual based answer to your question but more of an observance on my part.

I hope it gave you some ideas to research both fields and you will know what you see as a best fit. Because you could make either profession and have a great career

Like Mark said, both are great options for a career. I lead a design team and I have had architects in my team who were great designers and graphic artists. I will say this though, you can be an architect and change your field of career to be in design (visual design, interaction design) with few additional courses . I think the other way would be difficult. Become a graphic designer and change your career to be an architect. Hope it helps.

You are most welcome and good luck with your career pursuit. I am sure you will excel at anything you put your mind too!