Newbie Fishfinder question / help needed.

[Gunslinger]

I've never owned a fishfinder, although I've used an ancient Hummingbird a few times on a buddies bass boat. Anyhow, I'm in the process of getting things together to outfit my new (electric power only) Crappie/bass fishing boat. What I need input on, is what is the best fishfinder for under $200??? (or should I bite the bullet and raise my ceiling another 100 or so? I don't really want to, but if the pay-off is worth the investment........... . I will be using it primarily in lakes in water in the 4' to 40' depth range. I'm considering a Hummingbird 560 for $149.99 at BPS, but there are several other makes/models available in that price range, so I really don't know which unit will work best for me. Any input/suggestions are very much appreciated!!!