There are two schools of thought on this. One says: go for the best frame you can buy, then go for upgrades later. The other says: almost nobody keeps a frame for a lifetime or even more than a few years---so get the best overall bike you can afford and trade it out later. My belief is that a beginning roadie will have quite different needs and expectations from his bike, than an experienced rider.
If I could go back in time and counsel myself as a beginner, I'd recommend a mid-level steel frame (say Reynolds 631), with Shimano 105 level drivetrain...lots of bang for the buck. There are lots of aluminum frames out there, but the decnt ones are pricey. Ti and carbon bikes are for the more fanatical roadies who don't mind spending a grand or two just on the frame. You can get into the whole Campy-Shimano debate later---just keep an open mind.
Also I'd avoid any trick wheelsets, untill you've been around for awhile. They have their uses, but there are many pitfalls.
Your most important decision will be the bike shop you buy your road machine from! If they don't spend half an hour with you, taking measurements and asking questions about your riding experience and needs...well, you're just not going to get the right bike withe right fit.