First thing you do, make sure "Data in roaming" setting is off. Then install some software: Wifi tether (free), FastBright, MapDroyd, My Tracks, ACast (adware), GPS status (adware, getting ugly), K-9 Mail (free), Nimbuzz ($0, does it eat battery like crazy?), GeoBeagle (free, *), Facebook for Android ($0), ConnectBot (free).
There are even games worth playing: Flight director (demo), Bebbled ($0).
Security system shows its weakness when installing GeoBeagle -- it asks for sms sending permission. It will not use it, but... I'd be much happier if it was possible to install an application without giving it some permissions it wants.
Now.. I used to have nice application showing my GPS and CellID positions on the map -- so I knew what cell I was connected to. Unfortunately, I can't remember the name and can't find it on the market. Can someone help?
Are there applications / games I should know about?