OK, so it isn't really a New Years Resolution, but like Shawn, I am trying to be a little more green in 2008. To that end, we've changed a few things in our life:

• Last year we stopped buying bottled water for the house. I try not to buy it on the road, but that seems a near impossibility at times. Of course, research suggests that using a Nalgene bottle may expose me to Bisphenol A. I may have to buy a few of the Sigg bottles instead.
• I've started recycling more. After spending some time to determine what we can recycle in Atlanta, I have added more printed junk mail and cardboard to the outbound collection of recyclables. We already were very good about recycling plastic, glass and some paper products, so this is more of a tweak to our normal routine.
• Bye, bye printed catalogs! They fill up our mailbox every day. Catalogs from places like REI (which I want) and L.L. Bean (which I don't want). So I have used Catalog Choice to stem the flow. So far, no difference.
• "Free" newspapers that come in the mail aren't free to print, distribute and then haul to a recycling center. I called our local free newspaper and politely asked them to stop distributing to our home.
• Low flow toilets are great (well, sometimes) but they still account for a lot of our water usage. New motto: "If it's yellow, let it mellow. If it's brown, flush it down." A little urine in the toilet isn't going to kill anyone, but it will save a lot of water.
• Low flow showerheads are next on the list. I bought one already from Bricor, a 1.5 gallon per minute (GPM) model designed to save 1 GPM over my current showerhead, but I am disappointed with the results. The water pressure in my house may be part of the problem, but increasing the water pressure will cause more waste elsewhere. This one is going back to the manufacturer while I search for other solutions. (On this note, my water bill averages $35/mo. Another couple who are neighbors of ours have an average bill of $85/mo and some neighbors run $300+ bills in the summer. We're already pretty light users of water, it seems.)
• I am trying to get better at turning off the monitor, printer and other peripherals when they are not in use. Steph's machine automatically turns off when not in use. Since I'm almost always online I haven't yet gone down that route for my machines.
  

There are a few things we've done for years, too:

• Telecommute. I've been doing it for 3 years, full time. My car gets about 5000 miles/year traveling mostly to the airport and the gym. I figure this saves us 10 - 20k miles/year.
  
• Use automated thermostats and moderate the HVAC. Sure, I'd like it warmer in the winter and cooler in the summer, but that gets expensive quickly. The difficult part is when I work from home, I can't just heat or cool my office easily. I've looked into thermostats that automatically circulate air through the house even when the heat or AC are not needed, just to keep the temperatures even and air circulating. This may be a future change
• CFLs. Need I say more?

And then there are the things I can't or won't change. Admittedly, I could buy carbon credits, but I'm just not there yet:

• Air travel. I flew ~70k miles last year. Its my job and we love to travel.
  
• Inefficient cars. Sure, together we only drive ~25k miles/year, but neither car is particularly fuel efficient, at best we get 26 MPG in the Passat on a road trip. Considering that we drive an about average amount of miles in average fuel efficiency cars, this isn't all bad news. But it could be better if we had reasonable public transportation...
• Plastic grocery bags. They make good dog-poop bags. Two uses and I don't need to buy dog-specific bags.

What are you doing to reduce your ecological impact, if anything?