New vs. existing. You can make a case for either one. Here are a few quick pros and cons. A new home—built from the ground up with no previous owners—is typically more expensive to buy, but cheaper to maintain than a home that someone else has lived in. New homes are built to updated government codes and built for modern demands, with bigger closets and ample electrical outlets that some older homes lack. However, they're sometimes located far away from a community's center (which may be a plus to you), and there might be expensive homeowners dues. Existing homes, on the other hand, are usually found in more mature neighborhoods, where it's (presumably) easier to predict the area's future. Window treatments, lighting, decks, and landscaping are already in place, though sometimes design "flaws" are also built in, such as too few bathrooms or a miniscule kitchen.
Good timing can help. If possible, look for a home when the real estate market is going through a stagnant period, like around the December holidays. During these slower times, you can increase the chance of finding a seller who is more motivated to sell, and decrease the chance of other buyers competing with you for the same house.
Improving vs. maintaining. As a general rule, you can plan on spending from 1% to 3% of the purchase price on annual upkeep. Such maintenance and repairs include patching the roof, painting the bathroom, or hiring someone to mow the grass. These expenses differ from "improvements" which have a more permanent effect on your home. Installing a new roof, renovating a bathroom or landscaping the yard is an improvement. Be sure to save those improvement receipts for tax purposes.
Love at first sight. Becoming all knowledgeable and cerebral about home buying doesn't mean you won't get that rush of excitement when you find what you think is The One. Just try to keep those feelings in check. You don't want to fall hard for a home that winds up making you "house poor" for the next 30 years. It's best to find a home that's comfortable for you, both aesthetically and financially.