Ferengi yes, but I don't think Vulcans have been particularity stereotyped - aside from humans, they are probably the most multifaceted race in the Trek universe - with a huge range of motives, and breadth of 'emotion' (ironically). Romulans are pretty well treated too.
Poor portrayal of a human:
"Allah uh Akbar, Allah uh Akbar! I'm an Arab, look at my Gadaffi sunglasses, Arafat scarf, and Saddam hat. I SHOOT YOU! Death to the infidels!"
Good portrayal of a human:
I think people are confusing 'cultural idiosyncrasies' (fine) with 'poor charcterisation' (not fine) - portraying every Klingon with that same ridiculous arrogant growling personality is horrendous - mentioning logic a lot if you are a Vulcan is not, so long as you are written three dimensionally, and don't harp on too much. Basically, when it comes to Klingons, we are talking about poor drama / poor writing, to be blunt.
It seems racially selective - some aliens are done better than others - Klingons are probably the worst portrayed after TNG - other species aren't so badly handled.
Good Klingon portrayal:
Bad Klingon portrayal:
Pretty much everything after Heart of Glory lol.
Every scowling, rasping, one dimensional, needlessly confrontational, tiresome lot.