i heard that "crocs" were very comfortable. but as a "nurse" in college process. im not a nurse yet, just in process of becoming.
my 12 and 16 hour shifts at the nursing home, i found a similar shoe at Kmarts for 10.00. crocs sell for 30.00.
so, i tried kmarts. and these shoes are the most comfortable shoes.
i tried niki airs, "nursing shoes" that are made just for medical community persons. but my 10.00 kmart shoes that look like crocs are the most comfortable. my feet do not hurt in any way, and are still ready to go !!
hope this helps.

I too have had a really hard time finding the right shoe for work... ER 12 hour shifts, on your feet, running. Got Dansko Sports, LOVED THEM! Wore them for 2 years (32 hours per week) Just recently the heels wore out. Got a new pair...even better! Now they are going by a different name. But They are great! not so stiff and hard like regular Danskos. Got a lot more cusioning in the heel. (I too have heel spurs) Go to a Dansko dealer and ask for the new shoe that replaced the Sport. Mine are navy blue, and have a back to them so you won't kick them off by accident. They are rather expensive though, $120 US, but to me they are worth the cost. Additionally, I found that wearing burkinstocks clogs around the house off duty (especially right out of bed in the morning) really helped my heel pain. They keep your arch from flattening too much right after resting, so you don't tear stiffened connective tissue.... or something like that! Anyhow, it works for me! Hope this helps you!

Dansko shoes
I am currently looking for comfortable shoes as well. I have tried various tennis shoes, Croc's and I even spent over $100 on the Dansko shoes that other nurses raved about. I HATE my Dansko's...not only are they not very comfortable, but I find them extremely heavy. After 12 hours I feel as though I am using all of my energy just to lug my feet around. Just a warning before you spend a lot of money on them!