Not too easy of a question to answer.
One area you would look at is single user vs a multi user system.
If your application is to only have one user, then the expense and time of
setting up sql server likely would not be a good idea.
So, number of users is a good area to look at.
Security is another (sql server is more secure).
Size of data tables. If your tables are small..only in the 50,000 to100,000
record range..then ms-access is a great choice. if your table sizes are to
be in the millions..then sql server is likely better.
Target Market:
A small business with a few computers might not want to support, and setup
sql server.
There are many issues here.
Often, the kind of application you want to write is at issue