My reply to Trizz's beer post ran a little long and, I think, meritted its own posting.
I'd debate the fact that dark beers are more filling, especially with respect to Guinness. It's 100% perceptual and as such doesn't effect people without the perception problem.
You might feel you've eaten a loaf of bread after drinking a Guinness because you're intimidated by the sexiness of such a dark beer. Budweiser (the so called King of Beers) has an alcohol content of 4.82% and has 40 calories per 100 mL of beer. Guinness has an alcohol content of 4.27% and 43 calories per 100 mL. Yes, you read right, Bud is higher in alcohol than Guinness.
All beers are pretty close in caloric content (except lights, of course). Kirin Ichiban, a very light beer, is actually one of the highest calorie beer at 53 calories/100 mL and the grand prize winner is McEwans Scotch Ale at an amazing 83 calories/100 mL (yes, it's a dark beer and at 9.5% alcohol).
In my opinion, light beers can't compete with dark beers. I have to hunt high and low for a light beer that I will bother to drink. Most of those will be a light ale like Abita or Harp. To give light beer a break at all, I consider pale ales and amber beer light. I'm a big fan of over-hopped IPA. If you can hold a beer coaster behind your glass and still read what's printed on it, you're drinking a light beer.
The best beer made (if you can spend six bucks on an oversized bottle) are hand made by Trappist Monks like Orval or Westvleteren. Barring that, there are some bad ass brew pubs out there that hand make their beer with similar care. The best beer I've tasted was Waterloo Brewing Company's Porter beer that was nutty and smooth, 9% alcohol, easy to drink, and $1 a pint on Wednesdays.
Sadly, the pub was torn down to build a regional headquarters for Intel. Then Intel reneged on the deal leaving a giant concrete slab where my favorite beer used to be made. *wipes away a single beer tear*