Hopefully you'll have a sponsor who had similar circumstances as you (ie, has children) or they'll forget a lot of little details. We just PCSed here a few weeks ago and our sponsor, nice enough person, failed to mention a lot of little details that were major pains in the hiney to deal with once we were here as he was single when he PCSed here.
housing - I'd kill (well, no, not really - figure of speech) to live on PHV in officer's housing, the convenience just can't be beat. But yes, for temporary as well as long-term you want something that's on a school bus route. If you're going to be on the economy, I'd wait until you can visit the housing office, with patience you'll find a decent place in a decent village with a reasonable bus trip for your child.
Our stuff hasn't arrived yet but I can tell we're going to have a problem getting our bedroom furniture installed; on the top floors a lot of houses have low, sloping ceilings - do not bring your queen size canopy bed. As others mentioned, the houses will typically be 3 or 4 floors with a narrow, spiraling staircase, though allegedly the movers will use some sort of conveyor system to load furniture into the upper floors over the balconies and whatnot. I'll find out in another month or two.
On the other hand, if you have a really comfortable chair or couch that you love, bring it.
do not bring any 110v major appliances, just get the 220v appliances here. the transformers cost you money to use due to inefficiency, and the larger transformers (2,000W) may very well be unusable as they might trip the circuit breakers on their own (ask me how I know... ) The px in mannheim (20 minute drive) sells 220v appliances.
tv - the px sells multi-voltage multi-tuner tvs for an okay price, plan on getting one of them.
cable/internet/phone - easy - www.kabelbw.de - way cheaper than anyone else. I foolishly went with tkmobile; slower, more expensive and no cable tv.
do you have the study guide for the usareur driver's license yet? if not,
download it and take the test ASAP when you arrive. You need it before you can buy/register a car or buy the discounted gas.
Also worth noting, the first 60 - 90 days you will hate it here, guaranteed. It's an incredibly inconvenient place to get settled into, you'll spend a lot of time taking forms from one base to another, and most german businesses close early and aren't open on the weekends.
Is this your first overseas deployment? Notify your credit card companies that you'll be here (so they don't freeze your card), convert some $$ to euro before you come so you can shop/eat after you arrive (cash is king here) and don't forget your child's birth certificate. A GPS with european maps is hugely helpful as well.
There's probably a lot more to know - good luck.