So glad to see a post on bagels! I worship bagels! To invoke Calvin Trillin, they are so much more than just "round bread."
As far as enhancements and accompaniments, the purist in me insists that if a bagel is really good, it should be delicious just plain - no cream cheese, no butter, no wacko flavorings needed.
But the part that is...whatever the opposite of a purist is....admits to enjoying an asiago bagel or a blueberry bagel now and then. Still, it does seem to me that these enhanced tend to be inferior specimens to begin with.
When Manhattan Bagels first opened, they had a scrumptious cheddar cheese bagel - basically a really good plain bagel with chunks of orange cheese worked into the dough. The cheese bits melted slightly if you heated the bagel - wonderful! Then one day I went to get one, and found that the cheese-studded delicacy had been replaced by a bland, salty, uniformly orange, cotton-textured thing. I don't know if the switch was due to cost-cutting measures, misguided notions about customer preferences, or sheer indifference. But it really upsets me that something delicious and unique was abandoned in favor of something mediocre.
I'll stop ranting now...
(but for another bagel grievance, please see "Green Bagels" in "Miscellaneous-Food Related")