I used to work at a bakery (making pastries) and before that at a deli, and as a freelance caterer. Especially at the deli I sliced thousands of loaves of bread. We did not use a bread slicer, it was part of the deal that we sliced the bread (rye) and corned beef (or pastrami, turkey, roast beef, etc) by hand in front of the customers.
All that I have ever used to slice bread is a regular chef's knife (10-12"). At home I keep a few knives sharpened to a very aggressive finish (Actually I use a 100 grit AO belt on my belt sander as Cliff suggested above), and keep them honed on a deep groove Wustoff steel (14").
Serrations have not fared well, they will tear out fine breads, and the presentation will be sloppy.
While serrations may have some defensive applications (they would certainly tear up flesh), I am not conerned with that aspect of knife use. For all the knife work I do, a plain edge works best. IT can be changed from a slicer to a pushcutter ina few minutes and then back again.
I have a few "bread" knives that came with blocks of knives, I use them to saw through PVC pipe and such, they have no place in my kitchen.
Chad