Just to point you in a good direction, I'd suggest looking at the Silhouette, Pulse, Pilot, and Saffire 2. Read up on their flight characteristics (opening, snivel, stall, flare, control range, ect). its always best to try before you buy.
I have several jumps on a Silhouette 230, and I'm about 275-280 going out the door. The Silhouette 230 (according to PD's wing load chart) is maxed out at that weight, but it flies beautifully. I can practice all the my canopy drills on it like front riser dives and turns, rear riser turns and flares, but it is still a large and tame canopy.
I've also heard nothing but good about the Pulse. Many people are telling me that it is basically the next generation Silhouette.
I went with a Pilot when I bought my own. It's generally accepted as having the best openings on the market right now, and being a big boy, I feel those openings more than the average jumper. Once open, it flies a lot like the Saber 2 and just seems to have a wider range of use than the Silhouette did. It can be loaded light and used for students or loaded high and used for swooping.