OS X V10.7 Lion :: Gmail Recently Not Downloading Inbox?

I upgraded to Mac OS X 10.7.4 from 10.7.3 recently. Around the same time (shortly afterward, anyway), I started having a new problem.As of a few days ago, one of my Gmail accounts has stopped downloading the Inbox. I can log into the Gmail web site with that Gmail account and it shows the latest mail, but it does not show up in Apple Mail. I have done these steps: 

1. Get New Mail

2. Synchronize account

3. Disable and re-enable the account in Preferences

4. Checked the account shows up in the Activity window when I do these things

5. Quit and restarted mail

6. Took the account offline and online

7. Checked Connection Doctor

8. One other thing I can't remember what it's called, but it opens another window with a selector for all the accounts at the top and lets you look at various things

9. I can send mail successfully with that Gmail account 

All my other Gmail accounts (3-4 others) seem to be working fine, but of course the one that's broken is the one I use most often. The mail is showing up fine on my iPad and iPhone as well, so it's just Apple Mail that is "messing up." 

Info:
MacBook Pro (15-inch 2.53 GHz), Mac OS X (10.7.3), Aperture 3.2.3