I think when you start taking courses based on their usefulness (which is quite arbitrary; applied complex analysis will be useful for further study in QM say, Matrix Analysis will be great if you are also looking for further study of QM - it's easy to continue making up such examples) at this stage you'll find yourself in trouble.
This isn't like the first year where it is obvious basic Analysis is going to be more useful than Dynamics in the long run; the courses should start becoming specifically geared towards a niche sector.
For example if you're leaning towards Topology studying: topology, CA, Set theory, Group theory, field theory - for instance would be a good choice.
@Ultimate1; do you even lift?