Here is a small sample of beer, mainly light, and what the percentage of alcohol by volume is per calorie.
Notes:
1. Milwaulkee's best... "The Beast Light" gives hangovers!!
2. Miller light is ok at best
3. Mic Ultra Amber is my choice but Bud Select is a close competitor. So when I'm watching my waste but want a buzz, I'll switch up between the two.
4. When buzz and money are not an issue, Guinness Foreign Extra Stout every single time. It's filling and more expensive but oh so good.
Mix it up. Do a half and half, Guinness and Bud Select. Whatever makes you happy and keeps you skinny. Enjoy!

Update: Bud Select 55 clocks in at 55 calories 2.5 abv and 4.55% abv/calorie. I'll update further if I ever get around to trying it.
Umm.. it's ok. It's about as good as Bud Select, but you don't feel the buzz as soon so it doesn't taste better as fast.