That's the only one available out of the box in WSS 3.0. You can of course
build your own.

SharePoint Designer (if you're able to use it; it's free, BTW) gives the WSS
user a lot more workflow options than the OOB 3-state. And
SPDActivities.codeplex.com adds several more to that.

What are you hoping to do?

I am have a new site collection that will need some approval/customized
workflow settings. I am setting up a site collection for our group
overseas that will allow tracking of quotes and orders. Just basically
need some workflow that will allow for the approval and tracking of
items quoted. We will eventually want to expand on this, but I am unsure
of the specifics right now. I just know we were having trouble getting
the 3-state to work as desired. By the way, I am an administrator not a
developer, so please forgive the vagueness.

SharePoint Designer is the way to go. It gives you a great deal of functionality
regarding workflows for free.

And don't worry about "developer vagueness." If it doesn't meet your business
needs and/or can't be described in business language, it'll be useless to you
and your users anyway. :)

Another tool I've heard great things about (and I have NO affiliation with them
whatsoever... haven't even seen it in action) is Nintex Workflow. Standard
edition is somewhere just under US$9K; Enterprise is ~US$17K. It's a no-code
solution which allows you to visualize the workflow process (very similar to
what you would see in Visio) and it creates all the code for you.

And if/when you upgrade to SP2010, Visio itself has been purported to be a great
workflow builder that integrates right into SharePoint. (The demos sure look
exciting anyway!)

All that said, SharePoint Designer workflows are perhaps less intuitive than the
Nintex/Visio options, but at a pricetag of $0, it's worth taking a look.