The one feature that has been present in almost all the other debuggers I've used, and is apparently missing from GDB, is a standard hexdump - addresses, byte values, and ASCII. It's possible to emulate this with a bunch of extra steps, but the omission of such a simple feature is surprising. All the times I've had to use GDB the feeling I get from it is "makes very difficult things easier, but makes very easy things more difficult."