I'm looking to replace my 5 year old laptop.  I want my next laptop to endure at least this long.  I typically have Thunderbird, Firefox, Eclipse Java IDE, Skype, a ssh session, and Apache Tomcat running.  I'm currently running Karmic Ubuntu, but am agnostic about operating system and would move to Win 7 or OS X.  I frequently travel with this computer.  I also value battery longevity and power conservation (if possible).  Above all I'm looking to minimize cost.
I think the hardware that best meets my needs is an Intel i7 processor, 8 GB RAM, 100GB @7200 rpm or SSD hardrive, and about 15 inch monitor.  These specs are met by most brands.  
Does anyone know specific pros/cons and build quality for Macbook Pro, Lenovo Thinkpad (W510 or T510), Sony's VPC-F1190, and ASUS G Series G73JH-X1 NoteBook?  
Are all i7 processors created equal?  
Do you have other suggestion that meet my needs?