There are more opinions on this that you can shake a seatpost at. I would definitely stay under the $1,500 (new street price) for a bike. I've been riding and racing for a long time myself and spend considerably more money on bikes tha nthe average, but $1,500 is a good threshold for spending to "get in the door" with still good quality.

Then there is the triple VS double chain ring decision. This comes down to whether you want to ride fast and perhaps even race, or you are a more laid-back type rider and would never race. Double for racer/competitive types. Triple for laid-back types. There is a bit more to it than that, but that is the basics of it.

As far as brands go, I would probably stay with whatever is supported by any of the well established reputable bike shoips in your area. If you have a bike shop that sort of seems to specialize in racing or triathletes, this would be the best place to go, as they are going to know more about fit (which is key of course) than anyone else around.

If you go aluminum, which is the most popular bike material today, make sure it has carbon fiber seat stays. Those are the posts that run from the seat to the rear axle, else the ride will be quite harsh. A full aluminum bike frame is way harsh compared to its aluminum/carbon composite brethren. Or course, the front fork should be carbon, especially these days as this has become the standard. This grade of bike is going to have the best price point.

Then there are steel bikes. Steel is still a very good frame material. Some even still race on it. My wife's Orbea she races on is steel. Nice ride. Quite smooth on rough roads without the expense of exotic materials. On average, as steel frame will weigh about a pound more than an aluminum or carbon fiber frame. It will also cost a bit more, with the exception of "Race grade" aluminum frames. But it will not crack like aluminum can in time.

Finally there is titanium (although getting less popular) and full carbon fiber frames. I wouldn't go there for your entry level bike, as this will put you well past the $2,000 price point. Well past. The carbon fiber frames are the best for ride quality, weight, strength and about every other category. But you pay for it.

The next key area to look at is the groupo. That's all the gearing, shifters, chranks, etc. I never recommend anything below Shimano 105, which is what I would recommend in your case. You could go with Campoagnolo Centaur, but it will cost you more. There is Ultegra above 105, but that will push the cost up another $300-$400 and for antry level, doesn't make sense to do so. Anything at Shimano 105 or above will last a very long time, assuming it is well maintained.

The one place you DO NOT want to skimp on price is the saddle. Most entry level bikes come with a saddle that is, well, crap. While saddle fit is going to vary depending upon you sit bone width and a number of other variables, I will tell you the best saddles will appear to be a minamalistic looking saddles. They will also cost more than $75, as a general rule, although there are a few exceptions. But once you get those two little quarter sized sit bones toughened up in a few weeks, it will be WAY better than any of the big cushy or jell saddles you could buy. Sorry, but there is no way around toughening up those sit bones.