Hi JR92-
I have a Lowepro MicroTrekker 200. I bought it out of despiration, not for any particular love for the bag. But it's actually turned out to be quite nice. (Though I saw a few in some shutterbug ads that look NICE -- I'll try and find them and post information. They loaded different, and appealed to me more)
It works out well. I can carry my 1D with 70-200 f/2.8 L attached, a 28-70 f/2.8 L, the lens hood that fits those both, a 50 f/1.4, a flash unit that's about the same size as the Canon 550ex (soon to be replaced with a 550ex), the dummy battery and ac adaptor, a few CF cards and PCMCIA adaptors, some filters, paperwork, table tripod, etc.
The best part... it's really not all that big for everything I can fit in it. Granted, it weighs quite a bit fully loaded, but it's not big. It's about 13" tall, 5" deep, and 11" wide fully loaded.
Just snapped this. Despite my best try, I couldn't figure out how to take the photo with all the gear in the bag. 
http://www.pbase.com/image/3298265
Sorry for the bad photo -- Photoshop "LOW Jpeg Web Optimized" at it's worst. It looks squished in the photo because of how I have it leaning, but trust me it fills up nicely and is quite sharp.
I set the dividers at the top so that they form around the shape of the 1D. The flash goes in the photo's bottom right, the 50mm f/1.4 top right. I put flash cards and body caps in the middle right. The AC adaptor and filters go on the front of the bag. The table tripod fits into the small pocket on the front flap.
I took one of the extra little dividers and put it perpendicular under the 70-200 to help hold it a bit.
Jasper
P.S. - I paid $60-70 ($110 Canadian) for it. The Domke Spider 10 Backpack and the BUG Bag 20 are the ones that I would really love to get my hands on. They look very nice, but at $120 I would want to see it before I bought it. I haven't found any locally yet, though....