Google's Chrome browser is noted for being faster and smaller than Microsoft's Internet Explorer and Mozilla's Firefox. That's why it caught me by surprise when Gmail wouldn't load in Chrome but would open without a problem in Firefox and IE.
A quick Web search led to a thread on the Chrome Help forum dating back to March 2009 but updated as recently as this month. Several solutions to the Gmail slowdown were proposed in the thread, but it appears that Google engineers haven't yet figured out why Gmail sometimes balks in Chrome.
The fix that worked for me was clearing Chrome's cache. To do so, click the wrench icon in the top right of the browser window and choose Options > Under the Hood. Click the "Clear browsing data" button, select the items you want to delete, and choose "Clear browsing data" once again.
If clearing Chrome's cache doesn't get Gmail loading again, the simplest alternative workaround is to press Ctrl-Shift-N to open an incognito window prior to signing into your Gmail inbox. This temporary technique worked for me as well, but another proposed solution--using an encrypted connection (HTTPS) to open Gmail--didn't get my inbox to appear.
Google's advice for slow page loading
The Google Help page for Gmail-loading problems suggests you make sure your browser is up-to-date. Since Chrome updates automatically, this should be a no-brainer, but to make sure you have the latest Chrome version, click the wrench icon and choose About Google Chrome to open a window listing the version number and indicating whether an update is available.
Google's help site identifies three causes for the problem: a conflict with a security app or other software on your system, a browser cache in need of clearing, and a temporary outage of the Gmail servers. Disabling your security software is rarely a good idea, but it's okay to do so temporarily to see whether the app is the source of the problem.
The Gmail help page provides specific information for several security programs, as well as for a handful of browser extensions, including Better Gmail and Firebug. The page also lists instructions for clearing the cache, cookies, and other temporary files in IE, Firefox, Chrome, and Safari.
For possible solutions to other Gmail problems, scan the Gmail Known Issues page, which suggests remedies for about two dozen common Gmail glitches. The next time you encounter a problem with Gmail or another Google service, visit the Google Apps Status Dashboard to find information on recent outages.