Night Stand HD (US$4.99, also available in free Lite version) -- This good looking universal app not only gives you a choice of clocks, but you also have a world clock, multiple alarms, and a stopwatch. You can also see limited weather information right on the clock face. Unfortunately, the current lack of background capabilities on the iPad means you'll have to keep this app running in order for those alarms to ring on time, but that will be resolved with iOS 4.2 in November.
Touch LCD - Designer Speaking Clock ($1.99) -- If the jarring sound of alarm bells isn't your cup of tea, how about a universal app that speaks the time and provides spoken alarms? Touch LCD has an elegant LCD theme in five color schemes, and it can speak the time when the screen is touched, every time an alarm sounds, or at a chime interval (i.e., every 15 minutes). Since you'll want to have your clock running for the alarms to work, Touch LCD provides inverted colors and a dimmer to reduce the glare of the clock at night. There's also a stopwatch, world time clock, unlimited alarms, and a countdown timer. You can even set different alarm times for different days of the week and have those alarms repeat.
LCARS Clock for iPad ($0.99) -- Space, the final frontier.... Trek fans are going to love this "24th century alarm clock" with the familiar ST:TNG LCARS look and feel. It uses TNG-style sounds for alarms, provides a timer feature, and also does voice announcements. LCARS Clock now adds the StarDate to a display of the Earth date. This is a clock you'll want to "Engage!"
Math Clock ($1.99) -- If a regular clock isn't enough of a challenge for you, or if you're trying to stimulate the brain of your child, why not get Math Clock? It substitutes mathematical equations for the usual hours and minutes. For example, if the hours show 24÷2 and the minutes are displayed as 6 x 7, you know it's 12:42! There are three different levels of difficulty, depending on your math skills, and if those skills are lacking, you can touch an equation to get the actual time. This is a very different clock and a lot of fun.