I've always prefered to use "health care" as in "Health Care Law Blog." However, I often see it spelled the other way and often thought about the age old question he poses. Well, upon a quick search of online reasource I'm glad I found support for my use of the two-word version. Check out this and this and this. But see the American Heritage dictionary entry.
Going by Google hits -- "health care" is the more common usage. Healthcare (213,000,000 hits) vs. Health Care (325,000,000 hits).
Like Cobert maybe his post will start a national movement to change the Wikipedia entry for "health care" to show a preference for one spelling or the other.
As for HIPAA -- I always use whether someone spells it correctly to judge how knowledgeable they are about the subject. Per Google the stats are HIPAA (1,010,000 hits) vs. HIPPA (1,380,000 hits). It appears, based upon the results, that privacy officers and health care lawyers have a ways to go to educate the industry and public about HIPAA.