Here are my most recent mpg calcs on my 05 SE if anyone's interested. Vehicle has just under 18K on it now and since my last mpg post in June, I'm averaging 18.42 mpg. The X IMO seems to get better mpg with age!

LIFETIME AVERAGE: 17.47
AVG NOV 05 - FEB 06: 16.05
AVG FEB 06 - JUN 06: 17.08
AVG JUN 06 - OCT 06: 18.42

Vehicle purchased in late Nov 05, I drive ~60% + highway and tend to drive fast on the highway, 75-80mph. I use cruise ctrl a lot. I drive it, period not really trying to get better mpg. I'm using non-synth oil, regular gas and check tire pressures pretty regularly. Vehicle's bone stock and I couldn't be happier with mileage, performance, etc.

10.10.06 - 18.77 (323.6 / 17.424)
10.06.06 - 18.25 (336.6 / 18.436)
10.04.06 - 19.31 (318.1 / 16.465)
09.30.06 - 18.05 (304.4 / 16.864)
09.25.06 - 18.86 (341.8 / 18.118) AC
09.21.06 - 18.58 (317.8 / 17.097) AC
09.18.06 - 19.44 (304.7 / 15.673) AC
09.14.06 - 18.07 (173.0 / 09.573) AC
09.12.06 - 17.73 (263.1 / 14.832) AC
09.07.06 - 19.17 (379.6 / 19.800) AC
09.01.06 - 19.92 (249.8 / 12.540) AC
08.31.06 - 19.43 (340.3 / 17.506) AC
08.27.06 - 19.39 (242.3 / 12.495) AC
08.25.06 - 18.00 (329.2 / 18.284) AC
08.20.06 - 19.75 (358.1 / 18.128) AC
08.17.06 - 17.48 (263.5 / 15.067) AC
08.09.10 - 18.91 (284.3 / 15.034) AC
08.08.06 - 17.82 (331.2 / 18.580) AC
08.01.06 - 18.31 (284.5 / 15.537) AC
07.22.06 - 16.70 (309.9 / 18.556) AC
07.16.06 - 19.51 (276.0 / 14.143) AC
07.12.06 - 18.10 (210.0 / 11.598) AC
07.07.06 - 18.36 (290.1 / 15.794) AC
06.29.06 - 17.82 (318.2 / 17.850) AC
06.22.06 - 18.01 (316.4 / 17.564) AC
06.20.06 - 18.46 (258.6 / 14.005)
06.12.06 - 15.32 (224.9 / 14.671)
06.06.06 - 18.44 (202.2 / 10.962)
06.04.06 - 18.63 (262.8 / 14.103)
06.01.06 - 17.75 (332.0 / 18.695)
05.22.06 -
05.17.06 - 18.02 (312.6 / 17.339)
05.12.06 - 18.53 (333.0 / 17.970)
05.09.06 - 18.13 (330.9 / 18.250 )
05.03.06 - 16.42 (257.5 / 15.673)
04.21.06 - 18.91 (308.3 / 16.299)
04.16.06 - 17.11 (264.5 / 15.453)
04.09.06 - 17.49 (335.4 / 19.173)
03.21.06 - 16.16
03.04.06 - 15.64
03.01.06 - 15.48 (253.4 / 16.363)
02.22.06 - 15.67 (270.4 / 17.251)
02.16.06 - 14.18 (238.8 / 16.838)
02.08.06 - 16.80 (326.4 / 19.428)
02.03.06 - 16.33 (301.0 / 18.428)
01.27.06 - 16.06 (287.3 / 17.885)
01.24.06 - 15.63 (262.8 / 16.815)
01.18.06 - 15.60 (251.9 / 16.139)
01.14.06 - 15.74 (286.2 / 18.180)
01.06.06 - 17.12 (264.1 / 15.422)
01.04.05 - 15.25 (251.2 / 16.465)
12.30.05 - 14.89 (154.4 / 10.363)
12.23.05 - 15.61
12.19.05 - 16.12
12.15.05 - 15.13
12.05.05 - 16.60
12.02.05 - 17.83

LIFETIME AVERAGE: 17.47
AVG NOV 05 - FEB 06: 16.05
AVG FEB 06 - JUNE 06: 17.08
AVG JUNE 06 - OCT 06: 18.42

Note, I input the above info on my PDA to keep track of business miles. I started tracking mpg for the hell of it during break-in and just never stopped. Its nice to see a year's worth of data but my wife thinks I'm crazy to document like this (I think she's right).