I was using LastPass to check a few sites I use that weren't on the Mashable list, and rechecking some that said to check back, and here's a few that should now be changed, that people who visit this site are likely to have accounts with.

Comixology

Site:www.comixology.com
Server software:Apache
Was vulnerable:Possibly (known use OpenSSL, but might be using a safe version)
SSL Certificate:Now Safe (created 1 week ago at Apr 8 00:00:00 2014 GMT)
Assessment:Change your password on this site if your last password change was more than 1 week ago

Marvel (includes Marvel Unlimited)

Site:marvel.com
Server software:Apache
Was vulnerable:Possibly (known use OpenSSL, but might be using a safe version)
SSL Certificate:Now Safe (created 6 days ago at Apr 9 19:38:46 2014 GMT)
Assessment:Change your password on this site if your last password change was more than 6 days ago

Netflix - this is on the Mashable list, but has been updated to "change password"

Site:netflix.com
Server software:Not reported
Was vulnerable:Possibly (might use OpenSSL, but we can't tell)
SSL Certificate:Now Safe (created 6 days ago at Apr 10 00:00:00 2014 GMT)
Assessment:Change your password on this site if your last password change was more than 6 days ago

Vudu

Site:vudu.com
Server software:Apache
Was vulnerable:Possibly (known use OpenSSL, but might be using a safe version)
SSL Certificate:Now Safe (created 6 days ago at Apr 10 00:00:00 2014 GMT)
Assessment:Change your password on this site if your last password change was more than 6 days ago

ETA: checked us.playstation.com and got a "better safe than sorry" status.

Unable to get HTTP headers for us.playstation.com

Site:us.playstation.com
Server software:Not reported
Was vulnerable:Possibly (might use OpenSSL, but we can't tell)
SSL Certificate:Now Safe (created 2 days ago at Apr 14 03:39:03 2014 GMT)
Assessment:Change your password on this site if your last password change was more than 2 days ago

And lastly, I got an e-mail from Dark Horse comics saying to change my password.

Attention all Dark Horse Digital account holders:

The Heartbleed SSL bug has caused much concern over the past week. It allows hackers to easily view secure data such as passwords on affected web sites.

Upon hearing the news, we immediately patched our servers and replaced SSL certificates. We have not found any evidence that our systems were compromised in any way, but to be cautious we're still advising all customers to change their Dark Horse Digital password, especially if the password was used on any other website.