Great!. Firefox is what I use anyway.

FYI http://firstcoasthealthypets.com/sitemap.xml loads fine for me in Chrome. But I do see that you have a Chrome update available, maybe that's why.
In the left corner of browser screenshot the three bars are a different color indicating an update is available.

There is a way to view the xml-source-file, just go to the "view source" command in your browser menu (it's under developer tools). It will give you the native-xml, with all the angle brackets and everything. The Firefox browser will display the xml in its formatted form, using a stylesheet which is apparently what is tripping up Chrome.

As no one has mentioned this I'm wondering if it on my end only.

That happens to me often. I just have to click somewhere with a mouse and it will appear. It bugs me, but I haven't figured out how to solve it. Maybe it's a theme issue.

I'm on a different computer now, so I know it's a fresh cache, and I see the same thing when using Chrome. However, I just tried looking at it in Firefox, and I see the listing just fine! Every url in my site is listed (or at least I think so, it's a long list, but my site is less than two weeks old).

I think it's related to a non-Google friendly font issue.

I use Wordpress SEO by Yoast.

I actually deactivated the sitemap feature of the all-in-one before setting up the Google sitemap plugin, but maybe I'll do a full reinstall tomorrow, if it's still bothering me then. In the meantime, GWT reports they have the sitemap and reports no errors.

If you already have your sitemap plugin, then you need to ADD the name of it to the Webmaster Tools sitemap page. I think just having the 'map' but not officially adding it to Google isn't doing a darn thing.

The Webmaster Tools site actually recognizes my sitemap and reports no errors with it, so I think the only problem is that I cannot view the data in a browser.

This the error message I receive when I try to add sitemaps:
Your Sitemap appears to be an HTML page. Please use a supported sitemap format instead.
What am I doing wrong?

IIRC I think that's the message I was getting on GWT too. If you go to the top of the GWT page, where it says "add a sitemap", just put in your site name/sitemap.xml (if that's its name) and see what happens. In addition, down below on the same page, if it is listing your sitemap name and other pages from your website in a 1,2,3, list...just DELETE the other pages (by putting "check ticks" in the boxes provided) that appear below the sitemap name. That is what I had to do, and Google recognized it after that!

I'm off to bed now, gotta get up early! Good night :-)

G'nite! Thanks for your help.

There is a difference between xml and html. xml is just a structured data that uses tags like html, but they define data, not content. I'd say that your browser doesn't recognize your sitemap file because something is wrong in the very first line, it requires an <xml.....> tag and then a .
As far as generating it, the Google sitemap tool will notify Google of it (unless you tell it not to), so that the Google Webmaster Tools will see it. The Wordpress All in One SEO plugin has that option as well. Don't use both of them, there can only be one sitemap.

Thanks! I wasn't putting it in correctly. I saw Rbwnys' comment about XML and had a "D'oh!" slap the forehead moment. I had been putting in each page of my site and not the sitemap. It's working now.
~Amanda