For baseball sim fans,
iOOTP is going to be released tomorrow (5/5, should be in the store at midnight tonight).
Three good weather apps that don't suck balls like WeatherBug or TheWeatherChannelLite or whatever are typically the top weather apps in the App Store.
Wx Alert USA - I used to have a launcher for my local NWS page in Safari, but this app culls the National Weather Service forecasts. Nice and tidy to have all that info in one app, even if you only care about point forecasts (and therefore only use the first tab). Also has forecast discussions, graphical products, radar, satellite, etc. My one gripe is it downloads the entire package of data first (rather than on the fly) which can be kind of a pain if you don't have awesome up/down rates.
Fahrenheit - An app that tells you temperature at your nearest official reporting station (usually an airport). The cool thing about this is it pushes a badge (if you allow pushing) to your phone, so the icon itself shows the temperature without having to open any apps. Easy to see how warm it is outside when I get up and check my e-mail/etc. from bed.
RadarScope - This one most weather geeks have heard about, but it's the top radar app hands-down. Stupidly simple for those that just want to see "where is the rain?" and it even locks in on your GPS coordinates so you can pinpoint exactly where you are (obviously, a couple miles makes a huge difference if you are staring down the barrel of a supercell). Also gets data from rest of NEXRAD servers for all other radar stuff (velocities, vertically integrated liquid) if you-- are you know-- into that kind of thing.