CE? Well as far as I know a rom hack just changes the bytes in the file so any hex editor would technically work and CE does let you open a file, make changes, and save it (in 6.7 you have to explicitly save it, prior to that any changes were automatically saved to the file).
I think CE has a way to attach alternative binutils/disassemblers to it (since most roms don't use x86 assembly which is all CE supports by default), I've never used it so I don't know how it works... I also don't think it supports big endian values in the hex editor though which might be an slight annoyance, not sure how much since I don't usually with those myself.
If you haven't already you might look around where people have previously asked for the best hex editors for rom hacking, eg. http://www.romhacking.net/forum/index.php?topic=16348.0
Depends which system, I find the internal debugger of most systems to be more useful than CE and an emulator. I'm currently using a GameShark 64 Pro on my N64 that's wired up to the parallel port of a Gateway running Windows 95 and has the GS software. It allows me to pull dumps of RAM in to the software from the gameshark, and place breakpoints on certain areas of memory. Basically turns the N64 in to a debug unit.
However, I can understand if you have 0 of those things I mentioned, and figure an emulator and CE would be better suited.