Clydesdales/Athenas (200+ lb / 91+ kg) - Flat Bar for a Fat Boy?

I went out and bought a new decent bike to commute to work on, but find that most of the time I need to bring suits to the office and it just isn't convenient to ride to work...but I do get time during the day to go out riding, but the only place I can park a bike is down in the parking garage...so my $3000 road bike is out. Was thinking of getting a cheap flat bar to ride on a paved trail within 1/2 mile of the office. Any suggestions on a relatively cheap but workable bike?

A Navigator, or entry level Giant?

You could also go for a drop bar single speed. Performance has an '08 Scattante Americano (http://www.performancebike.com/shop/profile.cfm?SKU=25174&subcategory_ID=3040) for $300 right now.

Since you already have a road bike a mountain bike might be nice also. You could put a skinnier tire on it if you wanted or needed to. My son has a Trek 4300 that is a lower priced but very nice bike and the Hardrock series by Specialized gets lots of good reviews and is well regarded as a clyde ride.

I would get a used mountain bike on Craigs List. I see decent to better ones around here all the time for $100 or less. Then install slick tires or similar, and you are ready to go.

You might consider visiting the folding bikes forum and see if your situation warrants a folder. They say you can carry it in your car or on public transportation, wheel it in to stow at work, then go out lunch riding. Just a thought.