I've been riding for about a year now and started with a used moutain bike which was a Trek. I'm now riding a Trek hybrid fitness bike that's 15". Can someone tell me a good starter type road bike to consider and would a 15" be comparable to a size 47. I love the new Trek Madone 4.5 WSD but would this be too much bike for my first road bike? I'm riding about 15 miles 3-4 times a week now. Probably something a little cheaper would be nice too!