I disagree. You'll love the suspension on the Trek non FX bikes (the FX removes the front suspension and seat suspension). There is no maintenance listed in the manual for the front suspension and it's pretty much sealed and doesn't contain user-serviceable-parts If you're looking for a smooth ride from point A to point B then go ahead and get the suspension on the bike. Your butt and arms will thank you.

I would definately go for a bike purchased locally vs eBay. Your LBS will make it much easier for warranty items and tuneups and checkups - most of which will be free.

The Trek bikes you listed for the most part are pretty upright. You can put the stem down all the way and tilt the adjustable stem but you're still gonna be upright. If you want to ride hunched/leaned over then you want something like a road bike or a small bike with a high seat.

If you already have a MTN bike then just slap some less aggressive tires on it.

With that said and taking into account your local crime statistics getting a good used bike (check with your LBS) and making it look as plain as possible may be your ticket to peace of mind.

You might even consider a cheap, disposable walmart bike (did I just say that?) if there are problems with bikes getting stolen in your area. I'd hate to drop $350 on a bike and have it stolen or vandalized. With that money you could have purchased 4 walmart bikes.