Here are some handy command line options for VI Client:

-u (username)
-s (servername)
-p (password)

Example:

“C:\Program Files\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\VpxClient.exe” -u YOURUSERNAME -s SERVERIPADDRESS -p YOURPASSWORD

If you’re lazy, you can also edit your shortcut to VI Client:

“C:\Program Files (x86)\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\VpxClient.exe” -passthroughAuth -s SERVERIPADDRESS

Of course, for non 64bit systems this is:
“C:\Program Files\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\VpxClient.exe” -passthroughAuth -s SERVERIPADDRESS

This allows you to passthrough your logged-on username credentials.