There are some problems with Daedalus, one of which can be sound. If you want some other emuluators, check along the left frame of this site: http://xbox-emulation.dcemu.co.uk/
But if you want the best emulators (best I've found so far) for N64, you need to get Surreal64 through the same way you accessed some of the files to setup XBMC. You'll need another user name and password from the #xbins channel in mIRC and then use FlashFXP to access the files. Navigate your way through the various folders and download yourself whatever emulators you want. I've had a lot of luck with Surreal64xxx-beta 4.9 for N64 and Snes9-Beta 4 for super nintendo.
Be sure to unzip/rar it when FTPing to your box. Also be sure to direct your xbox where to look for the emulator and ROMs through the XboxMediaCenter.xml file.