Granted, I don't need alcohol to do karaoke, and can take it or leave it. It does help my nerves a bit, but I'll get up on stage whether I've been hitting the sauce or not. I've got a good voice, and I know not to pick sappy songs for a bar crowd. My favorite if the book has it and I think the crowd will get into it: "Hell" by Squirrel Nut Zippers. "Roadhouse Blues" is a close second, and it's in just about every karaoke book.
I am, alas, a lady with a deepish singing voice, and most songs by female singers are pitched too high for me to carry off well. I do a great Jim Morrison, though.