The most euphoric benzo, in my experience, is temazepam. It produces very enjoyable effects and exhibits all five main traits of benzos, and actually produces euphoria regardless of there being a condition of anxiety or not, unlike most benzos. I've heard triazolam is also euphoric but I haven't tried it. However, it is very weak; I've found that the sweet spot is 15mg and it is best enjoyed if you are not a frequent user of GABAergic substances and have a low tolerance.
The best recreational combinations containing benzos are situational, imo. For example, if you're the type to get anxious while smoking weed or irritated while taking opiates or have pre-existing anxiety and are taking pretty much any sedative or stimulant drug, taking it combination will make the experiences much more enjoyable. On the other hand, it can be dangerous since it can cause psychological habituation leading you to not be able to enjoy taking other drugs without taking benzos, which rapidly cause physical dependence, leading you to take benzos with other drugs just to feel normal. That being said, a good benzo/opioid/weed combo as an occasional experience is unmatched for those who are prone to experiencing anxiety or those who have occupational burnout.
edit: I misunderstood the OP, the most euphoric combination of benzos is temazepam and diazepam, in my experience. Alprazolam and diazepam also produced extreme situational euphoria by destroying the intense anxiety I was feeling during specific events.