I find my playboat is much easier to roll than my river runner, Leo... Every boat is different though!
We have a website for beginner/intermediate kayakers called http://www.coloradokayakers.com
which is for people just starting out on moving water up to people getting into class 4. It's for planning trips and finding paddle partners- there's over 100 people on it! Check us out if you're new to the sport.
My advice is to take a beginner class first, before you get your own boat. make sure you like the sport before investing in gear, because the gear is expensive and there is a WIDE variety out there. In addition to a boat, you need a sprayskirt, helmet, pfd, drytop, and paddle at a minimum.
It would be good to figure out what kind of boating you want to do before getting a boat, and try a LOT of them because it really is a personal preference as to which boat you get. Your 3 basic options for type of boating are: playboating (surfing, cartwheels, etc), river running (class 2-4ish), and creeking (dropping waterfalls and doing class 5/5+). There are boats specialized for each of these types of kayaking.
I'd probably start with a river runner or river running playboat for a first boat. They are forgiving, more playful than a creeker, but much more stable than a playboat. They punch through holes very well, and they turn on a dime. I think that they are the best of all worlds of kayaking.
River runners are great- usually they have flat, planing hulls so you can surf a little but you won't be able to do any other playboating moves other than surfing. I have a dagger GT which is awesome and I love it! It comes in 3 sizes- 7.5, 7.8, and 8.1. Robert, the mid-size would likely be the best of these for you. There's lots of other options, too, that I haven't paddled yet. Dogalot, maybe someone your size can recommend a river runner... I don't know of one for your size!
River running playboats are great too. You can surf and even learn to cartwheel and stern squirt, etc. but they are stable and great for river running too. The top of the line for this type of boat is the Wavesport EZ series and the Jackson Fun series. Robert- you would fit in the big EZ or the Fun (a larger to mid-size option). Dogalot, you would likely fit in the super EZ or the super fun.
Try a lot and see what you like... and take a lesson before buying. If you want to find partners to paddle with, join coloradokayakers, everyone's great on there!