i like how this thread has essentially been bumped from 4 years ago and is still going lol.
comfortably numb - completely agree with you, however, some benzos do definitely hold a sort of "edge" to others in terms of relative euphoria. for instance, flunitrazepam has actually given me full on, full blown euphoric feelings that are pretty damn similar to opiates. not the same, but definitely a strong body induced euphoric feeling and obviously the stupidness of the benzo ontop of that too.
i find benzos go nicely with stimulants sometimes as they can just take that edge off of them that can get slightly uncomfortable at times. for instance when i was tweaking my nuts off on methylphenidate, 0.5 of xanax really helped take away the nasty side effects but left me with the euphoria.
same goes for psychedelics - for instance LSD, valium didn't kill the high, but it did make it calmer. i'm not sure i wanted it to be calmer but i was essentially force fed one during a cid trip once because my friend was getting annoyed at me for making too much noise and said i should go to sleep. i knew the valium would do fuck all with regards to sleep, but it would shut him up once i'd swallowed it. to be honest i don't think it actually affected the LSD in any way at all, it just let me deal with some of the more intense parts of the LSD trip without freaking out.
some downers go well with benzos, the most common one (i think) is with opiates - i personally don't like that mix, i only really use it when i have an extreme tolerance to both substances normally. alcohol and benzos is usually a good one but in complete moderation, which is extremely difficult to do. it's also very dangerous to mix CNS depressants and i really don't recommend it whatsoever.