WTF happened to DIY? For the $50-$130 or whatever they are quoting for building the bike, with the info available online, just do it yourself. You will probably do it much better than the disinterested LBS employee will, and save yourself enough to buy some shorts or whatever.
Brent: You are riding 23s? Not sure what you weigh, but I would think 25s minimum (and mixing is no problem), and I would probably be looking at 28s. I really like the Conti GP4 Seasons 700x28s I have (~$100/pair including tubes shipped from Wiggle). Built on a GP3000 casing, so feel good, durable, much better than Gatorskins in my opinion in both feel and grip, particularly when wet out. Run less pressure than 23s, have better feel and just as fast.