I compare the Blue Nessie and the Blue Yeti USB microphones and recommend my personal favorite. This isn't me telling you which to pick, this is just my personal opinion on which one I'd personally recommend and pick.
I grew up with Playstation so I'm super partial to Sony, but ever since I made the switch to PC it's been a little hard to go back to console save for some exclusives.
Kevin MacLeod makes LOADS of royalty free music over at incompetech.com
That's where I get most of the music I used. For alternatives, you can always use video game soundtracks.
I'd recommend a Shure PGA27, but you should know that if you go with XLR to get a nicer sound, you'll have to get an interface that converts XLR to USB like the Focusrite Scarlett 2i2.