Ooh! This is an easy one since I own an XBOX 360, Nintendo Wii and a Samsung Galaxy Tab and I've tried all sorts of stuff like this before!

Nintendo Wiimotes and many Playstation 3 accessories are all bluetooth.
XBOX 360 wireless accessories are not Bluetooth. So, nope!

Even if you did get a headset and paired it successfully for phone calls, I've yet to hear or anyone successfully using bluetooth to do VOIP in Android in general (on any Android device). It seems that the microphone never wants to work with VOIP software. This might have been fixed in 2.3.x, now that VOIP is backed into the OS's phone stack--I haven't tried it on my Droid which is on 2.3.x yet, but I'm reasonably sure you aren't running 2.3.x on your Samsung Galaxy Tab anyway.

Yes. Oh God... yes. Plus the physical device is a LOT lighter than a Nook Color, even though the Nook Color is a thinner (generally smaller) device. It's a weird irony. The biggy here is that the camera--even just for barcode scanning ALONE--is worth it. Tethering the Tab to another device and using the GPS will ALSO be a very, very big deal and you'll thank me later for suggesting that it's worth it. The motion sensors seem to be the same on both, though I find the Galaxy Tab is a bit smoother about it.. but the Nook Color's is good enough to be useful and fun.

In the end, though, for the extra $100--GPS and cameras are VERY much worthwhile. Although, you also have to consider that the Galaxy Tab hasn't turned out to be the most hackable thing ever... the Nook Color is a hacking DREAM and virtually impossible to brick if you're a newbie that wants to learn how to root, ROM and throw CyanogenMod or Ultimate Droid onto the thing.

By the way, CyanogenMod 7 STABLE has been released (even though I'm still flashing nightlies onto my mom's tablet) and it's INCREDIBLY PERFECT now. It's definitely made the Nook a very, very responsive, beautiful tablet and it works GREAT! Video plays smoothly and at full-screen! The full-screen hacks are GREAT! Now you can force the status bar to STAY on the screen even with full-screen apps (like Angry Birds)... and even if you tap the DISAPPEAR button (to make the bar disappear), you can assign a REAPPEAR button to any key (I assigned it to the NOOK button) and it WORKS! Incredibly--it works GREAT! I'm impressed with the Nook Color and CyanogenMod combo! About the only two things I'm disappointed with, so far, is that there is no cifs.ko in the build for the Nook Color (so, no mounting Windows/Samba shares--fooey!) and the Bluetooth is still not working yet (apparently, they claim to be running into problems with the drivers or something).