I have a Necky Narpa (have had it for several years). The boat has a 'second rail' that allows you to tip about 15 degrees very easily, then hits this rail and is difficult to go past. The leaning makes the boat turn quicker. I've been extremely happy with it. I've had two other kayaks before - the original Chinook (the first plastic sea-kayak), and the Feathercraft (folding double kayak). I like the Narpa the best. My wife has an Arluk (sp?) fiberglass kayak - which seems nice (lighter and faster than mine), but I'm afraid to bash it in the surf.
In general, if you're looking for stability, keep with kayaks at or wider than 24'. The narrower style ('Greenland'

is faster, but as noted, very tippy. Not good for adverse conditions.
Incidently, I'm 6'1' and the Narpa fits me nicely. I've also done quite a bit of surfing with it, and it really handles well in the waves.
Your preferences may be different than mine, so it's best to try as many kayaks as you can get a hold of. The more you try, the better judgement you can make when it comes time to buy one. Good luck with your search!
- Charles