[QUOTE=earth]The only thing I can suggest for you is pay the extra to get disc breaks. They are worth their weight in gold.

Agreed they are beautiful but for a first bike I'd say they aren't all that necessary. Unless you start riding the muddy trails in K/W that is...

That said I have a few comments for this thread:
MrPerfect:
If you really want to get in shape there's nothing like bike commuting. A light MTB with slicks would be adequate for this but a road bike might be a little quicker. BTW in my opinion a "hybrid" is the worst of both worlds. If you think you'll do trails go for the MTB you can always swap tires depending on road vs. trail. If you are not into getting muddy and seeking out the trails go for a road bike and enjoy the awesome country roads north of waterloo and east of kitchener.

Nexus hub gears and brakes are a bad idea. Actually they are a good idea poorly executed. They generate tons of heat (wasted energy that could be making you go faster). They are also seriously heavy and force you to use custom built wheels (=$$$). My friend was a bike builder/designer and he experimented with these hubs in his search for the ultimate all weather bike. (we rode year round in Waterloo) Based on his experience I'd say go for a 24 speed (tougher and slightly more reliable than the 27-speeds). I taught my mom to use a 24-speed when she was 55. (she had only ever had 3-speed before). I'm sure you can learn it.

earth:
"powerline trails" in waterloo off the dead end of university ave. Fast not really technical but a large network of trails where you can get lost for 2+ hrs and not ride the same piece more than once. Tends to get very muddy if there's been any rain in the past 2wks!