Hi Chris, and welcome. I'm certainly not a veteran, but have had some experience riding a hybrid. I bought it a few years ago as a first bike (as an adult) and find it very comfortable because of the upright seating position. This is personal preference though and I understand that some road bikes have a more relaxed geometry. In my experience, I've traded speed for comfort.
As far as riding 50+ miles a day on your bike, it depends on your comfort. The only way to know is by trying it. I swear by my larger, Avenir plush saddle, but some members here prefer a smaller or more narrow one. Also the wider the tire, generally the more it will soak up the bumps and things in the road. Again, my only experience is on my 700x40c tires and the trade-off is slower speeds but better comfort.
My suggestion would be to put the money into the bike you already have, assuming it wouldn't be too expensive. The only way you can determine if it will be comfortable is by riding it.
Last edited by Passage4; 02-11-11 at 12:58 AM.