octarine and night86mare,
i know that the lens without filter usually yield the best result...but i am always paranoid that it gets dirty, water stains, cracked by a flying pebble (no matter how remote that chance is). A hood can protect it from knocks and probably drops(?)...
My lens all have a cheap tokina filter to shield it and sometimes, it gets water stains (i wonder where they come from?) and dust (dust is easy to rid with a blower though).
Do you shoot without filters too?