The starting point of any bicycle is the frame. Bike frames are available in a choice of materials and styles, so you will find one that will fit both you and your budget.
If you are looking for the more personal build, or perhaps upgrading your current frame, a new frame can make a big difference to your riding time. Alloy frames are perfect for the novice, commuter or junior cyclist. Carbon frames are lighter, stiffer, but more expensive, but do make a nice upgrade if you are coming from alloy. There are also steel and titanium frames which offer a lovely riding experience with a more classic design.