I have the guitar hero set which is a nice set, minus the foot pedal. I ended up getting an actual electronic drum kick sensor and placed it on an actual bass drum pedal and it rocked. I have not used the standard rock band drums or the new one with cymbals, but last week I did just get an Ion drum rocker pro set with 3 cymbals. This thing is a beast and will stand up to about anything, fully customizable, and with an add on can function as a fully capable electric drum set. The gh drums connect through a wiimote, and the ion kit attaches with usb. I believe the standard kit has a wireless dongle that it uses. I really enjoy using the ion kit, but rb drums do not work for gh games on the wii, I think they do for ps3 and xbox360 though. The gh set will obviously work for all full band gh games, and any of the rb2 and newer games (quite a few of the track packs, lego, beatles, green day, rb3). I would all but sell my gh drums if it were not for gh metallica. rb3 is king now. They have an amazing amount and variety of dlc, and the new pro modes offer much depth to the songs. I use gh 3 les pauls and they work will all of the music games just fine. I did get one of the new pro fender mustang guitar, which is insanely hard to use for someone like me that has played guitar professionally for the last 15 years. Novelty-wise it is pretty cool, but the reality is you need to know how to play the song already, note for note, how they do it. Needless to say I haven't used it that much. I would highly recommend the keyboard though, the pro mode is once again pretty tough, but on the normal setting it uses the normal color scheme and is a lot of fun. It can also do the guitar or bass parts if you aren't already using 2 guitars. Both the mustang guitar and the keyboard connect using separate wireless usb dongles, and neither one are supported by gh.
My recommendation would be to get a gh set for maximum compatibility. When using this set for rb3 I would use pro mode and you can turn on the orange cymbal to use as a green or blue cymbal in the game. I always though the rb guitars felt a little cheap and flimsy, and so I picked up some used gh les pauls on ebay. I would also invest rb3 and the keyboard. Lets face it, when playing with friends no one really wanted to sing that badly and many times no one did. The keyboard really opens the game up for 4 players, plus you can have up to 3 mics on some of the songs, making it 7 players!
Sorry to be so long winded, but I hope this clears a few things up!
P.S. As for the audible sound of the drums when being played, that is how all electronic drums sound, no getting around it. Turn up the sound, its rock and roll for god's sake.
