o hi dere.
I'm pretty new to snowboarding as well but just bought a Carbon Credit as my second board. I started on a GNU 11up (like a Rider's Choice in long & wide sizes) and just bought a never used Carbon Credit from last season. I rode it for the first time last weekend and really liked it. The banana ("rocker", "reverse camber") shape tech felt great. I was riding a real nice day with tons of fresh snow but with the banana I never felt like I was even close to catching an edge. The Magnetraction is cool. Never in the way when you don't want it and helps in less than perfect conditions! All these things will help make it an easy board to learn on. You'll like it if you haven't gotten out on it already!
Definitely don't cheap out on boots! Go ahead and get a good deal on lightly used stuff for the rest of your setup, but spend the extra on boots! If you find a deal on some boots that are practically brand new - maybe, but it's worth it to get a brand new boot because the liner and everything will start to mold to your foot as you ride it. You can even get lots of liners heat molded if you really want to. As the boots break in they might loosen up and you might find you get a little heel lift or a couple of other little problems, but those can be fixed fairly easily as long as you got a comfy, snug, well-fitting boot.
As for bindings and flex on everything - you might have to experiment a little to find out what you really like, but I do enjoy a little stiffness in my setup. Stiff means responsive, and that's important (in my opinion) when you're learning and need to make evasive moves quickly to avoid any trouble. The guys at the local shop I go to are all into park riding and hard freestyle so they tend to like soft stuff and also tend to recommend the same. The boots and bindings I got are both mid range quality Burton stuff and a 5 and 6 out of 10 on their flexibility ratings respectively. You'll have to experiment though and if you stick with it and get serious about it you may go through phases trying differing things and having evolving preferences.
Finally on mens vs ladies gear - since you're bigger than the tiny girls that I see on the slopes here, you might want to consider mens gear as well. As a taller guy I tend to have a pretty limited selection so I can already sympathize with you there
On the flipside, I rode with a girl on the weekend who had just bought a new high end womens Arbor board and she said it really made a difference. Primarily in the physical weight of the board and how much lighter and easier it was to ride.
Best of luck, enjoy your new found addiction, and hope to run into you out there!