It depends on several factors: Such as the space in your exercise area, any ankle, hip, knee or cardio constraints you may have and how much money you want to invest.

If you are planning on using a treadmill in your basement make sure that you have adequate floor AND HEADROOM space. Some less expensive treadmills fold up to take up less floor space but usually they are light weight and less durable than non folding machines. Also many people leave the platform in the down position anyway so it will still take up floor space. Factor in the height of your ceiling especially if you plan on running on an incline. Many basements only have an 8' ceiling (or less if you have a finished basement). We have seen many client homes that have dropped ceiling tiles remove so they can run without hitting the ceiling. However they also have to place the machine under the 2 X 4 open area which many not be where you want to place the machine.

If you have medical issues such as joint or cardio issues the safest (ie: least impact on the body) is a recumbent bike, followed by an upright bike, followed by an elliptical machine and finally a treadmill.

Finally, a $7,000 treadmill will hold just as many storage boxes and holiday decorations as a $2,000 one. We recommend trying out the equipment like you are going to use it. Don't let the equipment sales person sell you on features that are not important to you. At a minimum you want a durable 3HP motor and a polar compatible HR monitor receiver. Bring your workout clothes and workout on several pieces of equipment before you settle on the one for you.