I'm looking for the perfect object for transporting stuff on my commute. I'd like it to be all of the following, if possible:
1. Garment bag. I need to keep my clothes tidy and as wrinkle-free as possible.
2. Laptop bag.
3. Backpack. As my two-hour-each-way commute consists of a bike ride to the train station, a ride into Jersey City, and a walk to to the office, a pannier isn't the best solution.
4. Side water bottle carrier.
Cannondale CAAD8 (hot roddin') and a Scott SUB40 (commuter/tow-truck)
x2 on rolling the clothes. Works for me and I live in an office environment requiring straight clothing as well. It'll take a little practice to get it right and you don't want to do have your clothes rolled for too long, but pressed articles will survive a commute.
Topeak makes a pretty cool laptop bag. Just buy a heavy-duty rack. My corporate laptop + paperwork is pretty darn heavy.
I'll echo the messenger bag idea. Actually, I use a set of Timbuk2 tandem panniers. You can find then for around 90 dollars. They're a set of panniers that drape over your rack and are secured with Velcro and bungees. Plenty of room for a 15" laptop + power supply + water bottle in just one side, leaving the other side free for clothes. You can pull them off the rack and they magnet together to form a single bag with a messenger-style strap so you can wear it off the bike like a shoulder bag or a messenger bag.
Garment bags can be awfully large to carry on a bike's rack. That one looks mammoth, and it's not that much cheaper than a set of nice, versatile panniers or a large messenger bag. I can't see anyone needing a garment bag like that for a shirt, undershirt and pants.
I'm all for the backpack idea. I use one & just strap it to my rack when I'm on the bike. Rolling clothes is the way to go. I also keep a bottle of that Febreeze wrinkle releaser at work. (I know it's mostly just water). I rarely have to use it, but if I do get any wrinkles, this takes them right out.
There is a laptop sleeve you can buy that fits inside of it. Should work if you are smart about the packing.
If that isn't enough space for you, then get a rack with a dropped rail (i.e.Racktime Addit) and then add a trunk rack type of bag on top of it. The drop rail makes it compatible with the Bug. Suggestion would be the Arkel Tailrider but there are others.
Your commute sounds somewhat like mine. I have to do a combination of drive, ride a bus and ride my bike. so I need something that allows me to keep my hands free, pick the bike up and put it on the rack on the bus on the front. The Bug works.