Here's a shot of last year's Cascade Harvest Pale Ale (taken as part of my 1-pic-per-day photographic exercise last year - pm me if you've any interest in seeing 365 photos, many having beer relations). I sorta like the darker background and the sunlight playing off the foam - and I only kept it in the sun long enough for a photo, so no skunkiness! Another thing I think works well is a bit of obliquiness which adds depth (as opposed to that first photo showing a beer pretty much straight on.
