Wow, I really appreciate all the great information! This has been super helpful--I'm so glad I decided to post.

I rode a Jamis Ventura Race WSD today that I liked a lot. The shop spent the time to measure me and put me on a trainer, which I appreciated especially since I was looking at a bike in the lowest price range they carry. I'm 5'3 with a 30 inch inseam and long arms, so other shops have been putting me on 50-51cm frames where I've felt pretty comfortable--probably because I could keep the seat even with the handlebars and wasn't forced into a more aggressive stance. The guy today emphasized that a lot of people end up buying road bikes that are too big, and although I could have gone with either a 51 or 48 in the Jamis, I rode both of them and the 48 did end up feeling better.

EXCEPT, I'm not used to being so bent over handlebars and after riding around for 20 minutes or so, my arms were really tired! I'm not heavy or in bad shape, so I'm trying to figure out whether arm soreness means that the bike isn't actually the best fit or that I just need to get used to the different body positioning. Is arm soreness all part of the new rider experience? Then again, maybe a racy-type fit is less important for me? I'm just worried about getting a bike that doesn't fit correctly in the long run, as everyone has cautioned. It was also really hard for me to separate out the terrible pain the saddle was inflicting upon my nether-regions and good vs. bad fit! Yikes! I hear what you all are saying about leaving extra $$$ for accessories, as a new saddle will be a must!

The guy said there is some room to swamp out for a slightly more upright stem, so maybe that will help the arms. I plan to go back within the next few days to ride it and some of the other bikes again to compare after this new fit info and all the input from here.

Thanks again for all of the help! Lots to ponder....