I am careful with pronunciations as I have lived away from the UK for so long that I'm not really up-to-date. I accept that several words have changed, but even on Radio 3, you get people pronouncing words oddly, as if they'd only ever read them but never heard them spoken (harbinger, indictment are two examples that spring to mind - both heard on Radio 3 pronounced as they're written - really!)
But what annoys me the most is, as was mentioned above, the misplacing of emphases. Distribute and contribute are in transition as I write. While Jenny Murray says the conventional con-TRI-bute, her younger interviewee will be using the new CON-tibute. 
I hate to think what will happen when people start messing up the word "monotony".
And when I went to school, we had a couple of Northerners who said "haitch" - the rest of us said "aitch" but we never considered the one right and the other wrong.