looking for advice on a new bike...
 

OK, so I think my grandfather's Free Spirit is about cashed in, and while I'll keep it for a town cruiser, I doubt that it'll be up to distance commuting for much longer. Besides, it's just plain uncomfortable (I hate the "granny" handlebars, and the drops are too low for my seat height). So, I'm saving up my cash to buy a new commuter. Here's my criteria:

I weigh 200+ (at least for now), so strength is a factor
my commute fluctuates between 9.5 and 8.4 miles so comfort and pedaling ease is big
The roads are all paved, but are rough in stretches - gotta be strong (again)
Half is rather steep hills - gearing better than the shimano 3spd IH would be awesome
It'd be carrying fenders, wire panniers, my fat self, and a bookbag - all in all, about 250-275 lbs, depending on the day.



So, I'm not asking for a recommendation on the brand or make of the bike, since most of your suggestions would probably be out of my range (I'm looking for used, or a Bikes Direct cheapie), but in my situation, would you rather have a converted road bike, a hybrid or a MTB with slicks?

All three of those types of bikes could work. Frames that have eyelets and braze-ons for attaching fenders and racks would be best. If you are looking at road bikes, a touring or cyclocross style bike would be sturdy and have wide gearing range. I just wouldn't get a skinny tire racing bike.