TOTAL column or VIEW that computes?
I would go with the view for a few reasons:


It is obvious how the sum is generated with a view and it would always be correct.
You won't be able to fully trust the data of a updated column. ie life happens.  (The importance of this depends on the consequences of  bad data.)
This is essentially a premature optimization in a relatively lightly used system.


I don't think there is a good reason given the circumstances you described to go with the column/trigger/stored proc at this time.