I've now managed to get all of my FICO scores above the 600 mark, which is awesome. My highest score now sits at 630 (EX) where it seems to have stalled for the moment (it's been there for a couple of months now), but I'm hoping it'll continue creeping upward as I keep tackling old debts and rebuilding from past mistakes. So, the hard work is definitely paying off!
In other news, I was recently approved for an 800 limit with Amazon, which is awesome since they've always turned me down in the past. I was shocked when the CS rep on the phone congratulated me on my approval! It's a definite sign that my credit has improved significantly over the past few months. 
In addition, I just called Capital One today to ask about closing my secured card and opening a QS1 instead, since I currently have the Platinum Secured and a regular Platinum card, and kept getting told (when I applied for a QS1 card) that I can't add another "subprime" card - two is the limit, apparently. The rep told me that instead of doing that, she could upgrade my Platinum card to a Quicksilver card (not QS1, but actual QS!!! so no annual fee!), and then I could pay off the balance on the secured card and combine the two accounts into the QS card, so I'd have the same "spending power" of both limits, but only one card (with rewards). I accepted the offer and submitted the payment in full for the secured, so I can combine them. I love that that option exists! Not only will that keep me from losing $300 of my overall credit limits, which would hurt my utilization, but it would also open the door for me to apply for (and likely get approved for, according to the rep) a second unsecured card, if I want.
Once I get all of that done, and possibly open a second unsecured with Cap One (not sure if I want to do that or not at this point), I'll be back in gardening mode for the next while, while plugging away at old debts and such that are currently keeping my scores down.
All in all, though, I'd call this great progress!
Awesome!