<p>A long time ago when I was a young lat I used to do a lot of assembler and optimization programming. Today I mainly find myself building web apps (it's alright too...). However, whenever I create fields for database tables I find myself using values like 16, 32 &amp; 128 for text fields and I try to combine boolean values into SET data fields. </p>

<p>Is giving a text field a length of 9 going to make my database slower in the long run and do I actually help it by specifying a field length that is more easy memory aligned?</p>

Database optimization is quite unlike machine code optimization. With databases, most of the time you want to reduce disk I/O, and wastefully trying to align fields will only make less records fit in a disk block/page. Also, if any alignment is beneficial, the database engine will do it for you automatically.
What will matter most is indexes and how well you use them. Trying tricks to pack more information in less space can easily end up making it harder to have good indexes. (Do not overdo it, however; not only do indexes slow down INSERTs and UPDATEs to indexed columns, they also mean more work for the planner, which has to consider all the possibilities.)
Most databases have an EXPLAIN command; try using it on your selects (in particular, the ones with more than one table) to get a feel for how the database engine will do its work.