1) CO2 cartridges - Just so much easier that trying to get a decent pressure with a hand pump when you're sat at the side of the road in the cold and rain
2) Garmin edge 705 - Stops me getting lost and stores endless data for my inner geek to pour over when I get home
3) Powertap wheel - Makes training that much more precise, helps with pacing and see previous point about my inner geek
4) Northwave winter cycling boots - Nowt worse than cold feet
5) Tri bars - For that little extra speed