This is based on the Dell configuration that I have. The two laptops are roughly equal in price. ~$100, maybe.
Common specifications:
8600m GT 256MB
2GB DDR2 667Mhz RAM
15.4" 1680x1050 glossy display
Vista Home Premium
Dell:
9 cell battery vs. 8 cell for Asus
2.0MP camera vs. 1.3MP for Asus
3 years Complete Coverage vs. 2 year Manufacturer's Warranty for Asus
Logitec VX Revolution vs. Asus branded MX518 (well, this one may not necessarily be an advantage, who knows)
Asus:
T7500 vs. T7100 for Dell
160GB 5400RPM HDD vs. 120GB 5400RPM HDD for Dell
HDMI and eSATA vs. none for Dell
Merits of both. Fight.
Common specifications:
8600m GT 256MB
2GB DDR2 667Mhz RAM
15.4" 1680x1050 glossy display
Vista Home Premium
Dell:
9 cell battery vs. 8 cell for Asus
2.0MP camera vs. 1.3MP for Asus
3 years Complete Coverage vs. 2 year Manufacturer's Warranty for Asus
Logitec VX Revolution vs. Asus branded MX518 (well, this one may not necessarily be an advantage, who knows)
Asus:
T7500 vs. T7100 for Dell
160GB 5400RPM HDD vs. 120GB 5400RPM HDD for Dell
HDMI and eSATA vs. none for Dell
Merits of both. Fight.