Totally depends on your instruments/style/needs.
For ages I've been using typical 5-oct synths, but ever since I've been using an 8-oct masterkeyboard I'd never want to go back to 5 octaves again. So convenient for pianos and large drumkits, other instruments that feature "largeness" :P are harps and a full section of strings.
Now, you may not need those large instruments, but even synth voices could demand some range. The only question you need to ask yourself is: "what range do I need?"
For ages I've been using typical 5-oct synths, but ever since I've been using an 8-oct masterkeyboard I'd never want to go back to 5 octaves again. So convenient for pianos and large drumkits, other instruments that feature "largeness" :P are harps and a full section of strings.
Now, you may not need those large instruments, but even synth voices could demand some range. The only question you need to ask yourself is: "what range do I need?"