Generally, it seems that sentiment has changed as indicated by this Pew Research study that found 61% of Americans now support marijuana legalization. The numbers have basically flipped on this issue over the past 2 decades if you look at the graph there. Still, every individual will have have their own perspective based on their environment and experiences.
Although people might look at you funny if you are smoking in public, marijuana is becoming more socially acceptable. More people are realizing that the propaganda and anti-weed themes that many were raised on are not rooted in fact. As such, many of the "pot head" stereotypes are fading out, although they do still exist. The more marijuana is discussed and used, the more normal it will become and people will discuss it more freely. It's the same kind of idea with mental illness in this country - although mental illness is prevalent, few like to admit to being affected by and it's a sensitive subject because of the stigma attached to it. With weed, that stigma is dying out.
Like anything, it will take time and facts. As research continues to come out that details the health benefits of marijuana, the tide will continue to turn and it will begin to snowball hopefully.
Heck, I was able to go out on a date the other night and mentioned my affinity for marijuana and the girl was totally cool with it even though she wasn't a fan using weed herself. Everybody is different, but in the past, it seems like anytime I mentioned weed, people would jump right to the "stoner" stereotype and I'd be dismissed - regardless of how well I could speak to the subject. Seeing more people that are accepting of others using marijuana, even though they may not use it themselves, seems like a huge breakthrough. I'm seeing more and more people become less judgemental about weed, which is great, and contends that opinions ARE changing!
RE: Is the Stigma of Weed Going Away?