I've had my fixed gear for few weeks now. I commute to work on it a couple times a week, alternating with my road bike, (around 13 miles one way). I'm enjoying it a lot.
One thing I noticed, is it 'seems' like climbing hills is easier when i'm down in the drops, (track drops, same height as top of tire). I'm trying to figure out if it's just me thinking about it too much, or if it's normal/common.
edit: I should also note the head tube on my bike isn't very tall, it's a small bike, so the saddle/bar drop isn't as extreme as it might seem from the text above.
I've lowered the bars by one spacer since this pic was taken