I am presently a new triathlete with only 2 sprints under my belt.  am not fast, but it sure is fun. My wife and I just picked up two VERY nice bikes built by TREK. One of them is a Trek 2.1 that has a decent, robust drive train with Tiagra components, The carbon seatstays are nice, and aluminum hybrid frame provide a lively yet compliant ride. Not cheap at $1400 new but an awesome bike you can grow into. I myself went a little more on the deep end and bought myself a Madone 4.5. At 2K hardly entry level, but the value is very hard to beat with full carbon frame(TCT) and Shimano 105/Ultrega mix that even tolerates my unrefined shifting and rather large Clydesdale 220lb frame. This is a bike that you could race like a madman and still build up further. Ours is bone stock and I find the balance of performance and price quite hard to beat in either flavor of the 2.1 and the 4.5. These were 2008 models that you could probably STEAL this time of year in 2009, if you are lucky enough to find one leftover in your size. The 1.2 is also nice if you want to keep the budget under a grand. Other bikes you might want to consider are the Giant OCR 3, decent entry level machine that I saw at the time for only $650. Specialized Allie and Roubix are also nice for under $1500. KHS is also a less known company that may have something you might like. Keep in mind these are NOT time trial bikes, but offer a more relaxed geometry more suited for training and recreation.  Best advice I can give you. Make sure you spend what you can afford, BUT still if you can get something you can grow into, if you are going new. A decent local bike shop can be INDISPENSABLE in making a selection that can last you may years. Proper fit is a MUST if you ever intend to cover any distance at all in complete comfort. I have seen some of these bikes used for under $1000, on ebay and craigslist. Not easy to find, but occasionally you can. Best of luck in your endeavors, and selection of your new bike

Best. Regards, Dan2tri