I really like bar mitts/poagies for cold weather ($17 shipped - for more details). Adding these easily makes it feel 15 to 20 degrees Fahrenheit warmer than it actually is (not to mention they keeping the rain off of your gloves).

http://1.bp.blogspot.com/-xS8WyGt7-L...0/IMAG0569.jpg

Spring and summer: racing fingerless gloves.
Autumn and most of the winter: leather "driving" gloves. I endure cold very well and need not much insulation.
On really cold, -10C and colder days: skiing gloves.

My commute is 11 km one way, flat, with strong wind sometimes. If it were longer, I'd need better shoes/socks, but not sure about gloves.

Yes: Yoko makes some good ones as well. http://www.yoko.fi/products.aspx?category=2

I occasionally wear a pair of $1 cotton gardening gloves. It's about the right temperature outside now for this type of glove. I wore them this evening to the grocery store. Worked pretty good.

Spring, Summer and early Fall I wear fingerless gloves. In the cold I wear those brown cotton jersey gloves you see in convenience stores for about $2. They're good for me down to about 28°f. Below that I wear Loki mittens. They're convertible mittens and are warmer than hell. Those work down to -14°f. That's my personal low. But they're good sturdy gloves. The cotton jersey gloves, once they wear out they're easily replaced.

Depends on weather. All the gloves I use for biking are intended for biking. I have insulated gloves for subzero riding, uninsulated full-fingered gloves that are great for the 0-15º range, and fingerless gloves for long rides in warmer weather. Just for the commute I generally don't wear gloves in summer.

I use some generic stretchy/gel padded half finger gloves that I get off eBay for about $6/pair for when it's warm.

At medium temps (say, 45*F down to about 10*F) I wear "cold weather work gloves" from Harbor Freight, $15, very warm, waterproof, grippy, durable:
http://www.harborfreight.com/cold-we...rge-96606.html

At very cold temps (< 10*F, down to -25*F so far) I wear blaze orange "hunting gloves" which are basically cheap thinsulate lined ski gloves. They go on sale for $15 or so at the local department store when it's hunting season. Very toasty and very orange.