There's a whole ton of misinformation in this thread:
The only compromise involved users on the Steam forum. If you don't use the forum, there's no chance that your Steam account was compromised (and if you did, you'd have to use the same username or password to be at risk). You may have noticed that you didn't receive any e-mails alerting you to the hack if you don't use the forums.
Speaking of misinformation, here's a key highlight from Valve's announcement;
"
We learned that intruders obtained access to a Steam database in addition to the forums. This database contained information including user names, hashed and salted passwords, game purchases, email addresses, billing addresses and encrypted credit card information. We do not have evidence that encrypted credit card numbers or personally identifying information were taken by the intruders, or that the protection on credit card numbers or passwords was cracked. We are still investigating."