Without knowing the specifics about your site, I can't recommend one place over another. But consider these things as you make up your mind. Sunlight is important for plantings in or around your pond. Most water plants, such as water lilies, need 6-8 hours of sunlight a day to perform their best. You'll need a level site with well-drained soil. Though aquatic plants will be in the pond, you may want other kinds of plants (called marginal plants) around the perimeter.
Marginal plants can tolerate a bog, whereas most other plants grow best in soil with good drainage. Select a microclimate where your pond plants can grow in calm water. Strong winds can damage delicate water plants in a matter of minutes. Site your pond away from trees if possible. An extensive root system will make it more difficult to dig the hole for your pond, and roots may eventually cause liner problems. Also, leaves or needles from the tree will fall into the pond, clogging the pump and filter and clouding the water. The closer your pond is to a tree, the more skimming you'll be doing.
Consider how far away your pond is from electricity. You may need to consult a professional electrician about putting in a weatherproof electrical box near the site to plug in a pump or lighting. You'll also want a water supply nearby so you can top off the pond from time to time as needed