I decided to refresh my Dropbox install on Fedora 17 (now Fedora 18) from scratch and found the documentation of how to do that from the CLI a little conflicted. Here are the steps that worked for me.

Run the following commands as the user you want to be your Dropbox user:

cd ~  
curl -L -o dropbox.tar.gz http://www.dropbox.com/download?plat=lnx.x86_64 # use plat=lnx.x86 for 32-bit  
tar xzvf dropbox.tar.gz  
curl -L -o dropbox.py https://www.dropbox.com/download?dl=packages/dropbox.py  

If you're not going to be syncing to other systems on your LAN it's probably best to turn off LAN sync -- it's noisy! Then try and start up Dropbox.

python dropbox.py lansync n  
python dropbox.py start  

You'll get the following back from the Dropbox CLI script:

Starting Dropbox...Dropbox isn't running!  
Done!  

Run the start again:

python dropbox.py start  

And this time you'll get the URL to link your system:

To link this computer to a dropbox account, visit the following url:  
https://www.dropbox.com/cli_link?host_id=[base64 encoded hash]  

Plop that into a webbrowser and you'll be asked for your Dropbox password to confirm the link to the new machine.

Check the status to see if things are working:

python dropbox.py status  

You'll hopefully see something like: Starting...

Followed by:

Updating (390 files, 51 mins left)  
Downloading 390 files (523.2 kB/sec, 51 mins left)  

Magic!