Many divers want their dive computer to be able to grow with them, while they progress their diving. Almost all recreational dive computers have a Nitrox mode nowadays and a lot of them can even dive mixed gas, so you can switch between tanks with different gas mixes in them during your dive, which can be useful when you're doing a decompression stop on a tank with a higher oxygen percentage!
When you're looking for computers that can take you even further than that, make sure to have a look at computers that are made with the technical diving market in mind, such as the Scubapro G2 with its rec, tec and even sidemount mode and high resolution display!