Mr. Hoffman's thoughts on Choosing a Piano
If you decided to get in shape by running, you'd never think of going out every day for your run wearing cheap flip-flops. You'd make sure you had a good pair of running shoes. Learning the piano is no different.
I believe that it's important to practice on a quality instrument from the beginning, so that your body develops the correct habits of posture and your fingers develop strength and agility. Inexpensive keyboards have a spring action which requires much less finger strength than an acoustic or "weighted key" digital piano. If you practice consistently on a keyboard with a spring action, then later try to play on a real piano, you'll be very surprised and disappointed with how weak and clumsy your fingers feel.
If you're going to take the time to learn the piano, I highly suggest that you invest in either a quality acoustic piano (these can be quite expensive, around $5-7,000 USD) or, at least a quality digital piano with weighted keys. My favorite acoustic upright piano is the Yamaha U1, which is what we use at Hoffman Academy of Music. My favorite model for digital pianos with weighted keys is the Casio Privia. At Hoffman Academy, we have about 10 of these, and they are great instruments. With the Casio Privia you get a quality, powerful sound, and it feels almost exactly like playing a real acoustic piano, but at a much lower cost! Another nice thing about a digital piano is that you never have to get them tuned!
On the right, you can find a link to purchase the Casio Privia PX330, which is a great model with 250 built-in instrument sounds and 180 rhythms. I recommend getting it complete with the bench and stand, since if you just use a chair and table, your posture will not be as good, since a piano bench positions you at just the right height for playing (higher than a chair).
Make sure that you are getting the most use and enjoyment out of your piano practice by investing in a quality instrument that you can love playing for many years to come!