Between NASM and FASM which one would you pick?
And I pretty new to ASM but I think the Intel style looks better so I think that rules GNU out unless they have a Intel version syntax.
A good reason to pick NASM would be that you have at your disposal a great deal of resources (books, tutorials, example code, current users) to help you along the way. Of course, FASM was heavily enfluenced by NASM, so much of the material can be converted to something FASM can digest. However, such a task is easier accomplish by seasoned programmers -- thus it isn't recommended for a beginner.
In the end, it just comes down to personal preference.