Grammatical faux pas

I’m not exactly a purist, but I’m probably a little old fashioned when it comes to grammar. At the very least, I received my education and my upbringing in England and there’s not much I can do about that. Consequently, there are certain words and phrases in everyday use in North America which grate on me like chalk on a board.
They mainly occur in daily speech rather than in writing, and many have become accepted as natural developments of the language, but it seems to me that that defence is increasingly used to excuse sloppiness and errors.
Among my most loathed are:

• “This is as big of a problem as any” (I have no idea where the “of” came from, or what prompted the first offender to insert it, but he or she now has a huge following.)
• “I am finished my book” (My daughter’s favourite, this one - and yes, that was a sentence fragment. I will accept the intransitive “I am finished”, although only when the thing that is finished is the “I”, not a book or some other object or process. I will accept the transitive “I have finished my book”. I will not accept “I am finished my book.” Sorry.
• “How are you?” “Good!” (You mean as opposed to “Bad”? “Evil”? “Incompetent”? This one is well and truly entrenched in common usage now and, however much it chafes, I fear there is now no way back.)
• “It sounds real good” (Nah, it sounds real bad. This is another example of confusing adjectives with adverbs. Surely there must be a way back from this one. You only have to substitute an alternative word like "incredible", instead of "real" to realize that there is a "-ly" missing.)
• “The thing is, is I can’t change now” (I can’t believe anyone would ever write the double “is”, but it appears increasingly frequently in spoken language. I even heard it on the CBC the other day. I must admit, however, I had never noticed it until I read an article about its increasing use.)
• “I could of won” (No-one would say “I of won” instead of “I have won”, so where does this come from?)
• "I was like 'What do you, like, want?'" (Two different, equally repellent and equally incorrect uses of a word which I could happily see eradicated from the English language.)
• "Take the alternate road" (You mean every other road? There is, or at least there used to be, a very clear and distinct difference between "alternate" and "alternative" which I would not have thought particularly hard to grasp. The "alternate" American usage, seems to be becoming standard now, though.)
• "I will be with you momentarily" (Could you not spare me a little more time than that? As above, "momentarily" has a very definite meaning, and that is just not it.)
• "I have many bugbears, i.e. bad grammar, bad spelling, sloppy language, etc" (i.e. stands for "id est" and e.g. stands for "exempli gratia" - does that make it a little clearer?)
• "Save 50% off" (Offer me savings of 50%, or give me 50% off, but you don't need to do both!)

Americans (and possibly others) may argue that the language is evolving, and that I am just an old stick-in-the-mud. I would retort that, while I understand that languages evolve and change over time, I don't consider the institutionalization of errors to constitute evolution.
I don’t think I am being unduly finicky in complaining about these. This is not tricky stuff like “different to” and “different from” such as my old copy of Usage and Abusage agonizes over. It’s not nit-picking over the use of the possessive before a gerund, or the correct use of “whom”, or the perennial problem of “which” or “that”. I don’t even insist on not ending a sentence with a preposition.
But the examples above are just plain wrong and, if this is the way the English language is supposedly evolving, then I will fight it tooth and nail.