Xanax, hands down, worst tasting benzo.
Kpin is noms.
Etizolam tastes like Kpin, unless you suck on it (that blue coating that keeps the pill intact just tastes like plastic).
Lorazepam is also tasty, but I haven't noticed much difference in length of onset between sublingual and oral dosing.
I just had a single valium and I swallowed half, snorted 1/4 with some bupropion and yay, and plugged the rest of the pill with some bupropion and yay. From what I understand, both BP and CC will be active rectally, and I did read they made diazepam suppositories (though that may be in a different, more water-soluble form).
Considering classical diazepines are highly lipophilic (readily crossing fat membranes) absorption through other ROAs is possible, despite their insolubility in water.
I can tell you, snorting xanax mixed with your coke is the smoothest high ever. No anxiety, no increase in heart rate, just pure bliss.
I feel like I didn't make full use of my single valium however, since I didn't even thing to try sublingual dosing. It is the only benzo I haven't dosed sublingually. Even phenazepam was dosed (and overdosed) in that manner.
Word to the wise, avoid phenazepam.